C#.NET 7.

Harsha Vardhan

.NET Expert
Table of Contents
.NET -
Basics ............................................................................
.............................................. 23
Introduction to
.NET ..............................................................................
....................................... 24
Features of
.NET ..............................................................................
............................................. 25
Java (vs)
.NET ..............................................................................
.................................................. 27
Versions of
.NET ..............................................................................
.............................................. 28
.NET Framework (vs) Visual
Studio ............................................................................
................ 29
Versions of Visual
Studio ............................................................................
................................. 30
System Requirements of Visual Studio
2015 ........................................................................... 32

System Requirements of .NET Framework

4.6 ........................................................................ 33
Execution Model of .NET
Program ...........................................................................
................. 34
CIL (or)
MSIL ..............................................................................
.................................................... 36
CLR ...............................................................................
.................................................................. 37
CLS ...............................................................................
................................................................... 41
CTS ...............................................................................
................................................................... 42
FCL ...............................................................................
................................................................... 43
.NET Framework
Architecture ......................................................................
.............................. 37
C#.NET � Console
Applications ......................................................................
... 44
Introduction to
C#.NET.............................................................................
................................... 45
Project and
Solution ..........................................................................
........................................... 47
File Types of
.NET ..............................................................................
........................................... 48
Folder Structure of .NET
Program ...........................................................................
.................. 49
Tokens of
C#.NET ............................................................................
............................................. 50
Console Application Development in
C#.NET ......................................................................... 51

Console Application
Development .......................................................................
..................... 52
In C#.NET -
Example ...........................................................................
.......................................... 52
I/O Statements in
C#.NET ............................................................................
............................... 54
System.Console.WriteLine �
Example ...........................................................................
............ 56
System.Console.ReadKey
� .................................................................................
........................ 58
Example ...........................................................................
.............................................................. 58
System.Console.Clear -
Example ...........................................................................
..................... 60
Variables in
C#.NET ............................................................................
.......................................... 63
Variables -
Example ...........................................................................
........................................... 64
Data Types in
C#.NET ............................................................................
....................................... 66
Numerical Data Types in
C#.NET ............................................................................
................... 67
Numerical Data Types -
Example ...........................................................................
.................... 69
MinValue and
MaxValue ..........................................................................
.................................... 72
MinValue and MaxValue -
Example ...........................................................................
................ 73
Non-Numerical Data Types in
C#.NET ............................................................................
........... 75
char -
Example ...........................................................................
.................................................... 76
String in
C#.NET ............................................................................
................................................ 78
String -
Example ...........................................................................
................................................. 79
Bool in
C#.NET ............................................................................
.................................................. 81
Operators in
C#.NET ............................................................................
........................................ 83
Arithmetical Operators in
C#.NET ............................................................................
................. 84
Arithmetical Operators -
Example ...........................................................................
.................. 85
Assignment Operators in
C#.NET ............................................................................
.................. 88
Assignment Operators -
Example ...........................................................................
................... 89
Increment / Decrement Operators in
C#.NET ......................................................................... 92

Increment / Decrement Operators -

Example .........................................................................
93
Relational Operators in
C#.NET ............................................................................
..................... 95
Relational Operators -
Example ...........................................................................
...................... 96
Logical Operators in
C#.NET.............................................................................
.......................... 98
Logical Operators -
Example ...........................................................................
............................ 99
Concatenation Operator in
C#.NET.............................................................................
............ 101
Concatenation Operator -
Example ...........................................................................
.............. 102
Conditional Operator in
C#.NET ............................................................................
.................. 104
Conditional Operator -
Example ...........................................................................
................... 105
Control Statements in
C#.NET ............................................................................
..................... 107
If in
C#.NET ............................................................................
..................................................... 108
If -
Example ...........................................................................
...................................................... 111
If � Else -
Example ...........................................................................
............................................ 113
Else � If -
Example ...........................................................................
............................................ 115
Nested If -
Example ...........................................................................
......................................... 117
Switch � Case in
C#.NET ............................................................................
................................ 119
Switch � Case -
Example ...........................................................................
.................................. 120
While in
C#.NET ............................................................................
.............................................. 122
While -
Example ...........................................................................
................................................ 123
Do � While in
C#.NET ............................................................................
..................................... 125
Do � While -
Example ...........................................................................
....................................... 126
For in
C#.NET ............................................................................
................................................... 128
For -
Example ...........................................................................
.................................................... 129
Break in
C#.NET ............................................................................
.............................................. 131
Break -
Example ...........................................................................
............................................... 132
Continue in
C#.NET ............................................................................
........................................ 134
Continue -
Example ...........................................................................
......................................... 135
Goto in
C#.NET ............................................................................
................................................ 137
Goto -
Example ...........................................................................
................................................. 138
Nested For Loops in
C#.NET ............................................................................
......................... 140
Nested For Loops in C#.NET -
Example ...........................................................................
....... 141
Methods in
C#.NET ............................................................................
......................................... 143
Methods � Simple
Example ...........................................................................
............................ 145
Methods � Complex
Example ...........................................................................
........................ 147
Arguments and Return -
Example ...........................................................................
................. 149
Scope of
Variables .........................................................................
............................................. 151
Default Arguments in
C#.NET ............................................................................
...................... 152
Default Arguments -
Example ...........................................................................
....................... 153
Named Parameters in
C#.NET ............................................................................
...................... 155
Named Parameters -
Example ...........................................................................
....................... 156
Methods Overloading in
C#.NET ............................................................................
................. 158
Methods Overloading -
Example ...........................................................................
................... 159
Types of parameters in
C#.NET ............................................................................
.................... 161
Call by value -
Example ...........................................................................
................................... 162
Call by reference -
Example ...........................................................................
........................... 164
Call by output -
Example............................................................................
................................ 166
Type Conversion in
C#.NET ............................................................................
........................... 168
Implicit Casting in
C#.NET ............................................................................
............................. 169
Implicit Casting -
Example ...........................................................................
.............................. 170
Explicit Casting (or) Type Casting in
C#.NET..........................................................................
172
Explicit Casting (or) Type Casting -
Example ..........................................................................
173
Parsing in
C#.NET ............................................................................
........................................... 175
Parsing -
Example ...........................................................................
............................................ 176
TryParse in
C#.NET ............................................................................
......................................... 178
TryParse -
Example ...........................................................................
.......................................... 179
TryParse � Example
2 .................................................................................
................................ 181
Conversion Methods in
C#.NET ............................................................................
................... 183
Conversion Methods -
Example ...........................................................................
..................... 185
C#.NET � Object Oriented Programming (OOP) ............................ 187
Introduction to Object Oriented Programming in
C#.NET ................................................. 188
Objects in
C#.NET ............................................................................
........................................... 189
Data Members and Methods in
C#.NET ............................................................................
...... 190
Classes in
C#.NET ............................................................................
............................................ 191
Object Oriented Programming � Simple
Example ................................................................ 195
Object Oriented Programming � Advanced
Example .......................................................... 198
Console.ReadLine in
C#.NET ............................................................................
........................ 201
Console.ReadLine -
Example ...........................................................................
.......................... 202
Methods � Example 1 -
Age ...............................................................................
........................ 206
Methods � Example 2 -
Numbers ...........................................................................
.................. 209
Methods � Example 3 -
Login .............................................................................
....................... 214
Methods � Example 4 -
Student ...........................................................................
.................... 218
Constructors in
C#.NET ............................................................................
................................. 224
Parameterless Constructor -
Example ...........................................................................
......... 226
Parameterized Constructor -
Example ...........................................................................
......... 228
Constructors - Student -
Example ...........................................................................
................. 230
Object Initializer in
C#.NET ............................................................................
........................... 233
Object Initializer -
Example ...........................................................................
............................ 234
"this" keyword in
C#.NET ............................................................................
.............................. 237
"this" keyword -
Example ...........................................................................
............................... 238
"Set" and "Get" Methods in
C#.NET ............................................................................
............ 240
"Set" and "Get" Methods -
Example ...........................................................................
............. 242
Properties in
C#.NET ............................................................................
...................................... 244
Properties -
Example ...........................................................................
....................................... 246
Readonly and WriteOnly Properties in
C#.NET ..................................................................... 248
Readonly Properties -
Example ...........................................................................
..................... 249
Automatic Properties in
C#.NET ............................................................................
.................. 251
Automatic Properties -
Example ...........................................................................
................... 252
Objects as Arguments in
C#.NET ............................................................................
................. 254
Objects as Arguments -
Example ...........................................................................
.................. 255
Multiple Objects as Arguments in
C#.NET ............................................................................
. 257
Multiple Objects as Arguments -
Example ...........................................................................
.. 258
Objects as Data Members in
C#.NET ............................................................................
........... 261
Objects as Data Members -
Example ...........................................................................
............ 262
Inheritance in
C#.NET ............................................................................
.................................... 264
Inheritance -
Example ...........................................................................
..................................... 265
Inheritance � Example
2 .................................................................................
........................... 267
�base� keyword in
C#.NET ............................................................................
............................ 270
�base� keyword -
Example ...........................................................................
.............................. 271
Parent class�s constructor in
C#.NET ............................................................................
.......... 274
Parent class�s constructor -
Example ...........................................................................
............ 275
Method Hiding in
C#.NET ............................................................................
.............................. 279
Method Hiding -
Example ...........................................................................
............................... 280
Method Hiding � Example
2 .................................................................................
..................... 282
Method Overriding in
C#.NET ............................................................................
...................... 285
Method Overriding -
Example ...........................................................................
....................... 287
Method Overriding � Example
2 .................................................................................
............. 289
Abstract Classes in
C#.NET ............................................................................
........................... 292
Abstract Classes -
Example ...........................................................................
............................ 293
Abstract Classes � Example
2 .................................................................................
.................. 295
Abstract Methods in
C#.NET ............................................................................
........................ 298
Abstract Methods -
Example............................................................................
......................... 301
Abstract Methods � Example
2..................................................................................
............... 303
Interfaces in
C#.NET ............................................................................
....................................... 307
Interfaces -
Example ...........................................................................
........................................ 311
Interfaces � Example
2 .................................................................................
.............................. 313
Dynamic Polymorphism in
C#.NET ............................................................................
.............. 316
Dynamic Polymorphism -
Example ...........................................................................
............... 317
Dynamic Polymorphism � Example
2..................................................................................
..... 319
Multiple Inheritance in
C#.NET ............................................................................
.................... 322
Multiple Inheritance -
Example ...........................................................................
..................... 323
Interface Inheritance in
C#.NET ............................................................................
................... 326
Interface Inheritance -
Example ...........................................................................
.................... 327
Principles of Object Oriented
Programming .......................................................................
.. 330
Sealed Classes in
C#.NET.............................................................................
.............................. 333
Sealed Classes -
Example ...........................................................................
................................ 334
Namespaces in
C#.NET ............................................................................
.................................. 336
Namespaces -
Example ...........................................................................
................................... 337
Child Namespaces in
C#.NET ............................................................................
........................ 339
Child Namespaces -
Example ...........................................................................
......................... 340
Child Namespaces � Example
2 .................................................................................
............... 342
�using� statement in
C#.NET ............................................................................
........................ 344
�using� statement -
Example ...........................................................................
......................... 345
�using - alias� statement in
C#.NET ............................................................................
............. 347
�using - alias� statement -
Example ...........................................................................
.............. 348
Creating Separate Files for Classes in
C#.NET ...................................................................... 350
Creating Separate Files for Classes -
Example ....................................................................... 351
Partial Classes in
C#.NET ............................................................................
............................... 353
Partial Classes -
Example ...........................................................................
................................ 354
Enumerations in
C#.NET ............................................................................
................................ 358
Enumerations -
Example ...........................................................................
................................. 359
Structures in
C#.NET ............................................................................
...................................... 361
Structures -
Example ...........................................................................
....................................... 364
Structures with Constructors -
Example ...........................................................................
...... 366
Standard Data
Types .............................................................................
..................................... 369
The "System.Object" class in
C#.NET ............................................................................
.......... 370
�System.Object� Class -
Example ...........................................................................
.................. 371
Methods of "System.Object"
class .............................................................................
.............. 373
Methods of �System.Object� class -
Example ........................................................................
374
Boxing in
C#.NET ............................................................................
............................................ 377
Boxing -
Example ...........................................................................
............................................. 378
Unboxing in
C#.NET ............................................................................
....................................... 380
Unboxing -
Example ...........................................................................
......................................... 381
Static Data Members in
C#.NET ............................................................................
................... 383
Static Data Members -
Example ...........................................................................
.................... 384
Static Constructors in
C#.NET ............................................................................
...................... 387
Static Constructors -
Example ...........................................................................
....................... 389
Static Methods in
C#.NET.............................................................................
............................. 391
Static Methods -
Example ...........................................................................
............................... 393
Static Classes in
C#.NET ............................................................................
................................ 395
Static Classes -
Example............................................................................
................................. 396
Constant Data Members in
C#.NET ............................................................................
............. 399
Constant Data Members -
Example ...........................................................................
.............. 400
ReadOnly Data Members in
C#.NET ............................................................................
............ 402
ReadOnly Data Members -
Example ...........................................................................
............. 403
Generic Classes in
C#.NET ............................................................................
............................. 406
Generic Classes -
Example ...........................................................................
.............................. 407
Multiple Generics -
Example ...........................................................................
.......................... 409
Arrays in
C#.NET ............................................................................
............................................. 411
Arrays -
Example ...........................................................................
.............................................. 412
Arrays with For Loop in
C#.NET ............................................................................
................... 414
Arrays with For Loop -
Example ...........................................................................
.................... 415
Arrays with Foreach
Loop...............................................................................
........................... 417
in
C#.NET ............................................................................
......................................................... 417
Arrays with Foreach Loop �
Example ...........................................................................
........... 418
�System.Array� class in
C#.NET ............................................................................
.................... 420
�System.Array.IndexOf� method in
C#.NET ...........................................................................
421
�System.Array.IndexOf� method -
Example ...........................................................................
422
�System.Array.IndexOf� method � with NotFound -
Example ............................................ 424
�System.Array.BinarySearch� method in
C#.NET .................................................................. 426
�System.Array.BinarySearch� method -
Example .................................................................. 427
�System.Array.Clear� method in
C#.NET ............................................................................
.... 429
�System.Array.Clear� method -
Example ...........................................................................
..... 430
�System.Array.Resize� method in
C#.NET ............................................................................
.. 432
�System.Array.Resize� method -
Example ...........................................................................
... 433
�System.Array.Sort� method in
C#.NET ............................................................................
...... 435
�System.Array.Sort� method -
Example ...........................................................................
....... 436
�System.Array.Reverse� method in
C#.NET ...........................................................................
438
�System.Array.Reverse� method -
Example ...........................................................................
439
�System.Array.CopyTo� method in
C#.NET ............................................................................
441
�System.Array.CopyTo� method -
Example ...........................................................................
. 442
Multi-Dimensional Array in
C#.NET ............................................................................
............. 444
Multi-Dimensional Array -
Example ...........................................................................
.............. 445
Introduction to Collections in
C#.NET ............................................................................
........ 448
The "List" class in
.NET ..............................................................................
................................. 450
The "List" class -
Example ...........................................................................
............................... 451
The "List" class � with �for� loop in
C#.NET ...........................................................................
453
The "List" class � with �for� loop -
Example ...........................................................................
454
The "List" class � with �foreach� loop in
C#.NET ................................................................... 456
The "List" class � with �foreach� loop -
Example ................................................................... 457
"System.Collections.Generic. List.Add" method in
C#.NET................................................. 459
"System.Collections.Generic. List.Add" method -
Example ................................................. 460
"System.Collections.Generic. List. Insert" method in
C#.NET ............................................ 462
"System.Collections.Generic. List.Insert" method -
Example.............................................. 463
"System.Collections.Generic. List.AddRange" method in
C#.NET ..................................... 465
"System.Collections.Generic. List.AddRange" method -
Example ..................................... 466
"System.Collections.Generic. List.InsertRange" method in
C#.NET .................................. 469
"System.Collections.Generic. List.InsertRange" method -
Example .................................. 470
"System.Collections.Generic. List.Remove" method in
C#.NET ......................................... 472
"System.Collections.Generic. List.Remove" method -
Example ......................................... 473
"System.Collections.Generic. List.RemoveAt" method in
C#.NET ..................................... 475
"System.Collections.Generic. List.RemoveAt" method -
Example ..................................... 476
"System.Collections.Generic. List.Clear" method in
C#.NET .............................................. 478
"System.Collections.Generic. List.Clear" method -
Example ............................................... 479
"System.Collections.Generic. List.IndexOf" method in
C#.NET ......................................... 481
"System.Collections.Generic. List.IndexOf" method -
Example ......................................... 482
"System.Collections.Generic. List.IndexOf" method � Not Found-
Example ................... 484
"System.Collections.Generic. List.BinarySearch" method in
C#.NET ................................ 486
"System.Collections.Generic. List.BinarySearch" method -
Example ................................ 487
"System.Collections.Generic. List.Contains" method in
C#.NET ........................................ 489
"System.Collections.Generic. List.Contains" method -
Example ........................................ 490
"System.Collections.Generic. List.Reverse" method in
C#.NET ......................................... 492
"System.Collections.Generic. List.Reverse" method -
Example.......................................... 493
"System.Collections.Generic. List.Sort" method in
C#.NET ................................................ 495
"System.Collections.Generic. List.Sort" method -
Example ................................................ 496
System.Collections.Generic. List - Sort Descending -
Example ........................................... 498
Collection Filter in
.NET ..............................................................................
............................... 500
Collection Filter -
Example ...........................................................................
............................. 501
LINQ in
.NET ..............................................................................
.................................................. 503
LINQ -
Example ...........................................................................
................................................. 504
Collection of Objects in
.NET ..............................................................................
...................... 506
Collection of Objects -
Example ...........................................................................
.................... 507
Collection of Objects � Filter -
Example ...........................................................................
...... 509
Collection of Objects � LINQ -
Example ...........................................................................
....... 512
The "Dictionary" class in
.NET ..............................................................................
..................... 515
The "Dictionary" class -
Example ...........................................................................
................... 516
The "SortedList" class in
.NET ..............................................................................
..................... 518
The "SortedList" class -
Example ...........................................................................
................... 519
The "Hashtable" class in
.NET ..............................................................................
..................... 521
The "Hashtable" class -
Example ...........................................................................
................... 522
The "ArrayList" class in
.NET ..............................................................................
....................... 524
The "ArrayList" class -
Example ...........................................................................
..................... 525
The "typeof" operator in
.NET ..............................................................................
.................... 527
The "typeof" operator -
Example ...........................................................................
.................. 528
The "System.String" class in C#.NET (or) String Handling in
C#.NET ................................ 531
�System.String.Length� -
Example ...........................................................................
................ 535
�System.String.ToUpper� -
Example ...........................................................................
............. 537
�System.String.ToLower� -
Example ...........................................................................
............. 539
�System.String.GetChar� -
Example ...........................................................................
.............. 541
�System.String.Substring� � Example
1 .................................................................................
. 543
�System.String.Substring� � Example
2 .................................................................................
. 545
�System.String.Remove� �
Example ...........................................................................
............. 547
�System.String.Remove� � Example
2 .................................................................................
.... 549
�System.String.Insert� �
Example ...........................................................................
................. 551
�System.String.Equals� �
Example ...........................................................................
................ 553
�System.StringComparison. OrdinalIgnoreCase� �
Example .............................................. 555
�System.String.StartsWith� �
Example ...........................................................................
......... 557
�System.String.EndsWith� �
Example ...........................................................................
........... 559
�System.String.Contains� �
Example ...........................................................................
............ 561
�System.String.IndexOf� � Example
1 .................................................................................
.... 563
�System.String.IndexOf� � Example
2 .................................................................................
.... 565
�System.String.IndexOf� � Example
3 .................................................................................
.... 567
�System.String.LastIndexOf� �
Example ...........................................................................
...... 569
�System.String.Replace� �
Example............................................................................
............. 571
�System.String.ToCharArray� �
Example ...........................................................................
..... 573
Converting CharArray to String -
Example ...........................................................................
.. 575
�System.String.Split� �
Example ...........................................................................
.................... 577
�System.String.Trim� �
Example ...........................................................................
.................... 579
�System.String.Format� �
Example ...........................................................................
............... 581
�System.String.Reverse� �
Example ...........................................................................
............. 583
String � WordsCount -
Example............................................................................
.................... 585
String � Character Occurrence Count -
Example ................................................................... 587
String � Alphabetic Count -
Example ...........................................................................
............ 589
String � Word Occurrence Count -
Example ...........................................................................
591
String � Title Case -
Example ...........................................................................
.......................... 594
String � Currency into words -
Example ...........................................................................
....... 596
String � Multiple Concatenations -
Example ..........................................................................
600
The "System.Text.StringBuilder" class in
C#.NET ................................................................. 602
The "System.Text.StringBuilder" class -
Example ................................................................. 604
The "System.DateTime" structure in C#.NET (or) Date & Time Handling in
C#.NET ...... 606
The "System.DateTime" � First
Example ...........................................................................
.... 608
The "System.DateTime.Now"
�Example ..........................................................................
....... 610
The "System.DateTime" � Inner Values �
Example .............................................................. 612
The "System.DateTime.DayOfWeek" �
Example ................................................................... 614
The "System.DateTime.DayOfYear" �
Example ..................................................................... 616
The "System.DateTime. ToShortDateString" �
Example ..................................................... 618
The "System.DateTime. ToLongDateString" �
Example ...................................................... 620
The "System.DateTime. ToShortTimeString" �
Example ..................................................... 622
The "System.DateTime. ToLongTimeString" �
Example ...................................................... 624
The "System.DateTime" � Custom Formats �
Example ........................................................ 626
The "System.DateTime.Subtract" �
Example .........................................................................
628
The "System.DateTime.AddDays" �
Example ........................................................................
630
The "System.Math" class in
C#.NET ............................................................................
............. 632
The "System.Math.Abs"
�Example ..........................................................................
................. 634
The "System.Math.Floor"
�Example ..........................................................................
.............. 636
The "System.Math.Ceiling" �
Example ...........................................................................
......... 638
The "System.Math.Round" � Example
1 .................................................................................
. 640
The "System.Math.Round" � Example
2 .................................................................................
. 642
The "System.Math.Max"
�Example ..........................................................................
................ 644
The "System.Math.Min"
�Example ..........................................................................
................. 646
The "System.Math.Pow"
�Example ..........................................................................
................ 648
The "System.Math.Sqrt"
�Example ..........................................................................
................ 650
�System.Diagnostics.Process� class in
C#.NET ...................................................................... 652
�System.Diagnostics.Process� class -
Example ...................................................................... 653
Command Line Arguments in
C#.NET ............................................................................
......... 655
Command Line Arguments -
Example ...........................................................................
.......... 656
Nullable Data Types in
C#.NET ............................................................................
..................... 659
Nullable Data Types -
Example ...........................................................................
...................... 660
Exception Handling in
C#.NET ............................................................................
...................... 662
Exception Handling -
Example ...........................................................................
....................... 664
Destructor in
C#.NET ............................................................................
..................................... 666
Destructor -
Example ...........................................................................
...................................... 667
The "System.IDisposable"
interface .........................................................................
............... 669
The "System.IDisposable" interface -
Example ...................................................................... 670
Garbage Collection in
C#.NET ............................................................................
...................... 672
Garbage Collection -
Example ...........................................................................
....................... 673
Delegates in
C#.NET ............................................................................
...................................... 675
Single Cast Delegates -
Example ...........................................................................
................... 676
Multi Cast Delegates -
Example ...........................................................................
.................... 678
Events in
C#.NET ............................................................................
............................................. 680
Events -
Example ...........................................................................
.............................................. 682
Anonymous
Methods ...........................................................................
...................................... 684
Anonymous Methods -
Example............................................................................
................... 685
Lambda
Expressions .......................................................................
............................................ 687
Lambda Expressions -
Example ...........................................................................
..................... 688
Inline Lambda
Expressions .......................................................................
................................. 690
Inline Lambda Expressions -
Example ...........................................................................
.......... 691
Inner Classes in
C#.NET ............................................................................
................................. 693
Inner Classes -
Example ...........................................................................
.................................. 694
Indexer in
C#.NET ............................................................................
........................................... 696
Indexer -
Example ...........................................................................
............................................ 697
Assemblies in
C#.NET ............................................................................
.................................... 699
Class Libraries & Private Assemblies -
Example ..................................................................... 702
Shared Assemblies -
Example ...........................................................................
........................ 707
Access Modifiers in
C#.NET ............................................................................
.......................... 714
Access Modifiers -
Example ...........................................................................
............................ 717
Access Modifiers for
classes ...........................................................................
.......................... 720
Documentation
Comments ..........................................................................
............................. 721
Documentation Comments -
Example ...........................................................................
......... 722
Extension Methods in
C#.NET ............................................................................
...................... 724
Extension Methods -
Example ...........................................................................
....................... 725
C#.NET � Console - System.IO Namespace ..........................................
729
Introduction to "System.IO"
namespace .........................................................................
....... 730
The �System.IO.FileInfo�
class .............................................................................
..................... 731
The �System.IO.FileInfo� class -
Example ...........................................................................
.... 734
The �System.IO.DirectoryInfo�
class .............................................................................
.......... 736
The �System.IO.DirectoryInfo� class -
Example ..................................................................... 740
The �System.IO.Directory�
class .............................................................................
.................. 743
The �System.IO.Directory� class -
Example ...........................................................................
. 745
The �System.IO.File�
class .............................................................................
............................ 748
The �System.IO.File� class -
Example ...........................................................................
............ 750
The �System.IO.FileStream�
class .............................................................................
............... 752
The �System.IO.StreamWriter�
class .............................................................................
.......... 754
The �System.IO.StreamWriter� class -
Example..................................................................... 755
The �System.IO.StreamReader�
class .............................................................................
......... 757
The �System.IO.StreamReader� class -
Example ................................................................... 758
C#.NET � Console �
ADO.NET ...........................................................................
. 760
Database
Basics ............................................................................
.............................................. 761
Introduction to
ADO.NET ...........................................................................
............................... 763
ADO.NET � �SqlConnection�
class..............................................................................
.............. 765
SqlConnection � Windows Authentication �
Example ......................................................... 768
SqlConnection � SQL Server Authentication �
Example ...................................................... 771
The "SqlCommand" class in
ADO.NET ...........................................................................
.......... 774
ADO.NET -
ExecuteScalar .....................................................................
..................................... 777
SqlCommand � ExecuteScalar �
Example ...........................................................................
.... 778
SqlCommand � ExecuteScalar � Example
2 ............................................................................ 781
ADO.NET � Connection Oriented Model �
Introduction ...................................................... 784
The "SqlDataReader" class in
ADO.NET ...........................................................................
....... 786
ADO.NET � Connection Oriented
Model .............................................................................
... 788
ADO.NET Connection Oriented Model � Single Record �
Example ................................... 790
ADO.NET Connection Oriented Model � Multiple Records �
Example ............................. 794
The "SqlParameter" class in
ADO.NET ...........................................................................
........ 798
ADO.NET Connection Oriented Model � SqlParameter �
Example ................................... 801
ADO.NET Disconnected
Model .............................................................................
................... 805
The �SqlDataAdapter�
class .............................................................................
......................... 806
The �DataSet�
class .............................................................................
....................................... 807
DataSet -
Example ...........................................................................
........................................... 808
ADO.NET Disconnected Model �
Example ...........................................................................
.. 813
ADO.NET Disconnected Model � Multiple Tables -
Example .............................................. 817
ADO.NET Disconnected Model � Joins -
Example ................................................................. 823
ADO.NET Non Query - Insertion �
Example ...........................................................................
828
ADO.NET Non Query - Updation �
Example ...........................................................................
831
ADO.NET Non Query - Deletion �
Example ...........................................................................
. 834
ADO.NET Non Query � Insertion � With SqlParameter �
Example ..................................... 837
ADO.NET Non Query � Updation � With SqlParameter �
Example .................................... 841
ADO.NET Non Query � Deletion � With SqlParameter �
Example ..................................... 845
Stored Procedures Calling in
ADO.NET ...........................................................................
....... 848
ADO.NET Non Query � Insertion � With Stored Procedures �
Example ............................ 849
ADO.NET Non Query � Updation � With Stored Procedures �
Example ........................... 854
ADO.NET Non Query � Deletion � With Stored Procedures �
Example ............................ 859
ADO.NET -
Transactions.......................................................................
...................................... 863
ADO.NET � Transactions -
Example ...........................................................................
.............. 864
The "OleDb" namespace in
ADO.NET ...........................................................................
.......... 868
Connection Strings in
ADO.NET ...........................................................................
.................... 869
ADO.NET � Oracle -
Example ...........................................................................
......................... 870
ADO.NET � MS Access -
Example ...........................................................................
.................. 882
ADO.NET � MS Excel -
Example ...........................................................................
..................... 894
ADO.NET � SQL Server to Oracle -
Example...........................................................................
903
ADO.NET � SQL Server to MS Excel -
Example ...................................................................... 911
ADO.NET � Oracle to SQL Server -
Example...........................................................................
921
ADO.NET � Excel to SQL Server -
Example ...........................................................................
.. 929
ADO.NET � SQL Server to File -
Example ...........................................................................
..... 939
ADO.NET � File to SQL Server -
Example ...........................................................................
..... 944
The "SqlCommandBuilder" class in
ADO.NET ........................................................................
950
ADO.NET � SqlCommandBuilder � DataSet � Insertion -
Example ..................................... 951
ADO.NET � SqlCommandBuilder � DataSet � Updation -
Example .................................... 955
ADO.NET � SqlCommandBuilder � DataSet � Deletion -
Example ..................................... 959
N-Tier Architecture in
C#.NET ............................................................................
...................... 963
N-Tier Architecture -
Example ...........................................................................
....................... 964
LINQ to
SQL ...............................................................................
................................................. 972
LINQ to SQL -
Example ...........................................................................
.................................... 973
C#.NET � Console � Entity
Framework .................................................... 978
ADO.NET Entity
Framework .........................................................................
............................ 979
Entity Framework -
Example ...........................................................................
.......................... 982
Entity Framework � FirstOrDefault -
Example ....................................................................... 987

Entity Framework � Insertion -

Example ...........................................................................
...... 992
Entity Framework � Updation -
Example ...........................................................................
..... 997
Entity Framework � Deletion -
Example ...........................................................................
.... 1002
C#.NET � Windows Forms
Applications ................................................ 1007
Introduction to Windows Forms Applications in
C#.NET .................................................. 1008
The �System.Windows.Forms.Form�
class ............................................................................
1010
Programming Model of Windows Form in
C#.NET ............................................................. 1011
Windows Forms Application � First
Example .......................................................................
1013
Form Constructor -
Example ...........................................................................
........................ 1015
Properties of �System.Windows.Forms.Form�
class .......................................................... 1017
�System.Windows.Forms.Form. Text� property -
Example ............................................... 1020
�System.Windows.Forms.Form. ShowIcon� property -
Example ...................................... 1022
�System.Windows.Forms.Form. ShowInTaskBar� property
-Example ............................. 1024
�System.Windows.Forms.Form. MinimizeBox� property -
Example ................................ 1026
�System.Windows.Forms.Form. MaximizeBox� property -
Example ............................... 1028
�System.Windows.Forms.Form. ControlBox� property -
Example ................................... 1030
�System.Windows.Forms.Form. TopMost� property -
Example ....................................... 1032
�System.Windows.Forms.Form. WindowState� property
�Example ............................... 1034
�System.Windows.Forms.Form. FormBorderStyle� property �
Example ........................ 1036
�System.Windows.Forms.Form. Cursor� property -
Example............................................ 1038
�System.Windows.Forms.Form. BackColor� property -
Example ..................................... 1040
�System.Windows.Forms.Form. BackgroundImage� property �
Example ...................... 1042
�System.Windows.Forms.Form. Size� property -
Example ................................................ 1044
�System.Windows.Forms.Form. Location� property -
Example ........................................ 1046
�System.Windows.Forms.Form. Icon� property -
Example ................................................ 1048
Events of �System.Windows.Forms.Form�
class ................................................................. 1050
�System.Windows.Forms.Form. Load� event -
Example .................................................... 1051
�System.Windows.Forms.Form. Shown� event -
Example ................................................. 1053
�System.Windows.Forms.Form. Click� event -
Example ..................................................... 1055
�System.Windows.Forms.Form. DoubleClick� event -
Example ....................................... 1057
�System.Windows.Forms.Form. MouseClick� event -
Example ........................................ 1059
�System.Windows.Forms.Form. MouseMove� event -
Example ....................................... 1061
�System.Windows.Forms.Form. KeyPress� event -
Example ............................................. 1063
�System.Windows.Forms.Form. FormClosing� event -
Example ...................................... 1065
�System.Windows.Forms.Form. FormClosing� event - Example
2 ................................... 1067
Methods of �System.Windows.Forms.Form�
class ............................................................. 1070
�System.Windows.Forms.Form. Hide� method -
Example ................................................. 1071
�System.Windows.Forms.Form .Show� method -
Example ............................................... 1073
�System.Windows.Forms.Form. Close� method -
Example ............................................... 1075
Introduction to Windows Forms Controls in
C#.NET ......................................................... 1077
�System.Windows.Forms.Label�
class .............................................................................
...... 1079
�System.Windows.Forms.Label� class -
Example ................................................................ 1082
�System.Windows.Forms. Button�
class .............................................................................
.. 1086
�System.Windows.Forms. Button� class -
Example ............................................................. 1090
�System.Windows.Forms. Button� class � with Image -
Example ..................................... 1094
�System.Windows.Forms. Button� class � with Label -
Example ...................................... 1098
�System.Windows.Forms. TextBox�
class .............................................................................
1103
�System.Windows.Forms. TextBox� class -
Example .......................................................... 1108
�System.Windows.Forms. TextBox� class � With AutoComplete -
Example .................. 1112
�System.Windows.Forms. TextBox� class � With AutoComplete � Example
2 .............. 1116
�System.Windows.Forms. TextBox� class � With KeyPress �
Example ............................ 1120
�System.Windows.Forms. TextBox� class � With KeyPress � Example
2 ........................ 1124
�System.Windows.Forms. TextBox� class � With Enter and Leave �
Example ............... 1128
�System.Windows.Forms. TextBox� class � With TabIndex �
Example ........................... 1133
�System.Windows.Forms. TextBox� class � Math �
Example ............................................ 1137
�System.Windows.Forms. NumericUpDown�
class ............................................................. 1143
�System.Windows.Forms. NumericUpDown� class �
Example .......................................... 1147
�System.Windows.Forms. DateTimePicker�
class ............................................................... 1151
�System.Windows.Forms. DateTimePicker� class �
Example ............................................ 1155
�System.Windows.Forms. MonthCalendar�
class ................................................................ 1159
�System.Windows.Forms. MonthCalendar� class �
Example ............................................ 1163
�System.Windows.Forms. ToolTip�
class .............................................................................
. 1167
�System.Windows.Forms. ToolTip� class �
Example ........................................................... 1169
�System.Windows.Forms. ErrorProvider�
class ................................................................... 1173
�System.Windows.Forms. ErrorProvider� class �
Example ................................................ 1175
�System.Text. RegularExpressions. Regex�
class ................................................................ 1179
�System.Text. RegularExpressions. Regex� class �
Example ............................................. 1181
�System.Windows.Forms. MaskedTextBox�
class ............................................................... 1186
�System.Windows.Forms. MaskedTextBox� class -
Example ............................................ 1190
�System.Windows.Forms. CheckBox�
class ..........................................................................
1194
�System.Windows.Forms. CheckBox� class -
Example ....................................................... 1197
�System.Windows.Forms. RadioButton�
class ..................................................................... 1201
�System.Windows.Forms. RadioButton� class -
Example .................................................. 1204
�System.Windows.Forms. ComboBox�
class ........................................................................ 1209

�System.Windows.Forms. ComboBox� class -

Example ..................................................... 1212
�Cascading ComboBox� -
Example ...........................................................................
.............. 1216
�System.Windows.Forms. ListBox�
class .............................................................................
. 1221
�System.Windows.Forms. ListBox� class -
Example ............................................................ 1224
�System.Windows.Forms. CheckedListBox�
class ............................................................... 1228
�System.Windows.Forms. CheckedListBox� class �
Example ............................................ 1231
�System.Windows.Forms. TreeView�
class ...........................................................................
1235
�System.Windows.Forms. TreeView� class -
Example ........................................................ 1240
The �System.Windows.Forms. PictureBox�
class ................................................................ 1245
�System.Windows.Forms. PIctureBox� class -
Example ..................................................... 1248
�System.Windows.Forms. PIctureBox� class � Example
2 ................................................. 1251
The �System.Windows.Forms. Panel�
class ..........................................................................
1256
�System.Windows.Forms. Panel� class -
Example ............................................................... 1259
The �System.Windows.Forms. GroupBox�
class .................................................................. 1263
�System.Windows.Forms. GroupBox� class -
Example ....................................................... 1266
The �System.Windows.Forms. SplitContainer�
class .......................................................... 1270
�System.Windows.Forms. SplitContainer� class -
Example ............................................... 1273
The �System.Windows.Forms. TabControl�
class ................................................................ 1277
�System.Windows.Forms. TabControl� class -
Example ..................................................... 1280
The �System.Windows.Forms. FlowLayoutPanel�
class ..................................................... 1284
�System.Windows.Forms. FlowLayoutPanel� class -
Example .......................................... 1287
�System.Windows.Forms. LinkLabel�
class ...........................................................................
1291
�System.Windows.Forms. LinkLabel� class -
Example ........................................................ 1294
�System.Windows.Forms. WebBrowser�
class .................................................................... 1298
�System.Windows.Forms. WebBrowser� class -
Example .................................................. 1300
�System.Windows.Forms.Timer�
class .............................................................................
..... 1304
�System.Windows.Forms. Timer� class -
Example ............................................................... 1306
�System.Windows.Forms.Timer� class � with Time -
Example ......................................... 1310
�System.Windows.Forms.Timer� class � with Counter -
Example ................................... 1314
�System.Windows.Forms.Timer� class � with Slide Show -
Example ............................... 1318
�System.Windows.Forms. ProgressBar�
class ...................................................................... 1323
�System.Windows.Forms. ProgressBar� class -
Example ................................................... 1326
�System.Windows.Forms. NotifyIcon�
class .........................................................................
1330
�System.Windows.Forms. NotifyIcon� class -
Example ...................................................... 1333
Popup
Boxes .............................................................................
................................................. 1337
PopupBoxes -
Example ...........................................................................
................................. 1338
�System.Windows.Forms. ColorDialog�
class ...................................................................... 1346
�System.Windows.Forms. ColorDialog� class -
Example .................................................... 1348
�System.Windows.Forms. FontDialog�
class ........................................................................ 1353

�System.Windows.Forms. FontDialog� class -

Example ..................................................... 1355
�System.Windows.Forms. FolderBrowserDialog�
class ..................................................... 1359
�System.Windows.Forms. FolderBrowserDialog� class -
Example ................................... 1361
�System.Windows.Forms. OpenFileDialog�
class ................................................................ 1365
�System.Windows.Forms. OpenFileDialog� class -
Example ............................................. 1367
�System.Windows.Forms. SaveFileDialog�
class ................................................................. 1371
�System.Windows.Forms. SaveFileDialog� class -
Example ............................................... 1373
�System.Windows.Forms. MenuStrip�
class .........................................................................
1377
�System.Windows.Forms. MenuStrip� class -
Example ...................................................... 1382
�System.Windows.Forms. ContextMenuStrip�
class .......................................................... 1387
�System.Windows.Forms. ContextMenuStrip� class -
Example ........................................ 1390
�System.Windows.Forms. ToolStrip�
class ...........................................................................
1395
�System.Windows.Forms. ToolStrip� class -
Example ......................................................... 1400
�System.Windows.Forms. StatusStrip�
class ........................................................................ 1404

�System.Windows.Forms. StatusStrip� class -

Example ..................................................... 1409
�System.Windows.Forms. RichTextBox�
class ..................................................................... 1413
�System.Windows.Forms. RichTextBox� class -
Example ................................................... 1418
User Controls in
C#.NET ............................................................................
.............................. 1432
User Controls -
Example ...........................................................................
............................... 1433
Windows Forms Control
Library ...........................................................................
.................. 1439
Windows Forms Control Library -
Example ..........................................................................
1440
�System.Net.Mail.SmtpClient�
class .............................................................................
......... 1447
�System.Net.Mail.SmtpClient� class -
Example ................................................................... 1449
Multi-
Threading .........................................................................
............................................... 1455
Multi Threading -
Example ...........................................................................
........................... 1458
Task Parallel
Library ...........................................................................
...................................... 1462
Task Parallel Library -
Example ...........................................................................
.................... 1464
Windows Services in
C#.NET.............................................................................
...................... 1468
Windows Services -
Example ...........................................................................
........................ 1469
C#.NET � WinForms � System.IO Namespace .................................. 1474
The �System.IO.FileInfo� class -
Example ...........................................................................
.. 1475
The �System.IO.DirectoryInfo� class -
Example ................................................................... 1480
The �System.IO.Directory� class -
Example ..........................................................................
1486
The �System.IO.File� class -
Example ...........................................................................
.......... 1490
The �System.IO.StreamWriter� class -
Example................................................................... 1495
The �System.IO.StreamReader� class -
Example ................................................................. 1498
C#.NET � WinForms �
ADO.NET ...................................................................... 1502

SqlConnection � Windows Authentication �

Example ....................................................... 1503
SqlConnection � SQL Server Authentication �
Example .................................................... 1507
SqlCommand � ExecuteScalar �
Example ...........................................................................
.. 1511
SqlCommand � ExecuteScalar � Example
2 .......................................................................... 1515
ADO.NET Connection Oriented Model � Single Record �
Example ................................. 1519
ADO.NET Connection Oriented Model � Multiple Records �
Example ........................... 1524
ADO.NET Connection Oriented Model � Multiple Records - Label �
Example............... 1529
ADO.NET Connection Oriented Model � SqlParameter �
Example ................................. 1534
ADO.NET Connection Oriented Model � SqlParameter � ComboBox � Example ..........
1540
DataSet -
Example ...........................................................................
......................................... 1547
ADO.NET Disconnected Model �
Example ...........................................................................
1554
ADO.NET Disconnected Model � Multiple Tables -
Example ............................................ 1559
ADO.NET Disconnected Model � Joins -
Example ............................................................... 1567
ADO.NET Disconnected Model � Record Navigations -
Example ..................................... 1573
ADO.NET Disconnected Model � ComboBox -
Example .................................................... 1582
ADO.NET Disconnected Model � ComboBox - DataSource -
Example ............................ 1589
ADO.NET Disconnected Model � DataGridView -
Example ............................................... 1596
ADO.NET Disconnected Model � DataGridView - SqlCommandBuilder - Example .......
1600
ADO.NET Disconnected Model � Master � Child �
Example .............................................. 1605
ADO.NET Disconnected Model � Cascading ComboBox �
Example ................................ 1611
ADO.NET Non Query - Insertion �
Example .........................................................................
1618
ADO.NET Non Query - Updation �
Example .........................................................................
1622
ADO.NET Non Query - Deletion �
Example ..........................................................................
1626
ADO.NET Non Query � Insertion � With SqlParameter �
Example ................................... 1630
ADO.NET Non Query � Updation � With SqlParameter �
Example .................................. 1636
ADO.NET Non Query � Deletion � With SqlParameter �
Example ................................... 1642
ADO.NET Non Query � Insertion � With Stored Procedures �
Example .......................... 1647
ADO.NET Non Query � Updation � With Stored Procedures �
Example ......................... 1653
ADO.NET Non Query � Deletion � With Stored Procedures �
Example .......................... 1659
ADO.NET Disconnected Model � ComboBox � Stored Procedures � Example ..............
1664
ADO.NET Disconnected Model � Updation with ComboBox -
Example .......................... 1671
ADO.NET � CRUD (Create, Retrieve, Update, Delete) -
Example ..................................... 1679
ADO.NET � Registration Form -
Example ...........................................................................
.. 1694
ADO.NET � Login Form -
Example ...........................................................................
............... 1701
ADO.NET � Transactions -
Example ...........................................................................
............ 1709
ADO.NET � Oracle -
Example ...........................................................................
....................... 1714
ADO.NET � MS Access -
Example ...........................................................................
................ 1727
ADO.NET � MS Excel -
Example ...........................................................................
................... 1740
ADO.NET � SQL Server to Oracle -
Example.........................................................................
1750
ADO.NET � SQL Server to MS Excel -
Example .................................................................... 1758
ADO.NET � Oracle to SQL Server -
Example.........................................................................
1768
ADO.NET � Excel to SQL Server -
Example ...........................................................................
1776
ADO.NET � SQL Server to File -
Example ...........................................................................
... 1786
ADO.NET � File to SQL Server -
Example ...........................................................................
... 1792
ADO.NET � SqlCommandBuilder � DataSet � Insertion -
Example ................................... 1798
ADO.NET � SqlCommandBuilder � DataSet � Updation -
Example .................................. 1804
ADO.NET � SqlCommandBuilder � DataSet � Deletion -
Example ................................... 1810
N-Tier Architecture -
Example ...........................................................................
..................... 1815
LINQ to SQL -
Example ...........................................................................
.................................. 1825
C#.NET � WinForms � Entity Framework .............................................
1832
Entity Framework -
Example ...........................................................................
........................ 1833
Entity Framework � Insertion -
Example ...........................................................................
.... 1841
Entity Framework � Updation -
Example ...........................................................................
... 1848
Entity Framework � Deletion -
Example ...........................................................................
.... 1855
Part 1 - .NET - Fundamentals
Introduction to .NET

What is .NET?

� .NET is an �application development platform�, which is used to develop

applications.
� .NET is developed by Microsoft Corporation in 2002.

Parts of .NET

� .NET is mainly divided into 3 parts:

1. C#.NET (C Sharp .NET)
2. ASP.NET (Active Server Pages .NET)
3. ADO.NET (ActiveX Data Objects.NET)

1. C#.NET
� Covers language basics.
� It is used to develop �Stand-alone applications� that runs based on
the single machine.
� Ex: Calculator, Bill Generation Applications etc.

2. ASP.NET
� Convers server side programming.
� It is used to develop �Enterprise applications� that runs based on
�Client-server architecture�.

3. ADO.NET
� Convers database interaction.
� It is used to connect to databases in both �Stand-alone applications�
and also in �Client-server applications�.
Features of .NET

Features of .NET (or) Design Goals of .NET

1. Object Oriented
2. Many types of applications
3. Language Independency
4. Platform independency

1. Object Oriented:
. .NET is fully object oriented.
. It supports all the features of object oriented programming, such as �Re-
usability�, �security�, �classes�, �objects�, �encapsulation�, �hiding�,
�abstraction�, �inheritance�, �polymorphism� etc.

2. Many types of applications:

o Before .NET, we have to use different languages to develop different
types of applications (like console apps, windows apps, and web
apps).
o But in .net, using the same language, we can develop all types of
applications.

3. Language Independency:
. .NET is language independent.
. That means we can write .net programs in many .net languages. The
developers can choose any .net language, based on their interest and
knowledge. In all the .net languages, concepts are common but syntaxes
are different.
4. Platform independency:
. Platform independency means "ability of an application compiled in one
operating system can be run in other operating systems".
. .NET is �platform independent�, by using some third party tools such as
�Mono�, prior to .NET 4.6.
. From .NET 4.6 onwards, .NET is �platform independent� by using a built-
in tool called �.NET Core�. That means it supports many operating
systems, such as Windows, Linux, Mac, Android, iOS.
Java (vs) .NET

Differences between Java and .NET

Concept

Java

.NET

Language /
platform

Java is a language;

.NET is a �development platform�,

which is a collection of many languages
and frameworks.

Vendor

Java was developed by SUN

micro systems; recently it is
taken over by Oracle Corp.

.NET is developed by Microsoft Corp.

Language
independency

Java is a single language; it

doesn�t support multiple
languages.

.NET supports many languages.

Programming
concepts

Structures, partial classes,

properties etc., are not
supported by Java.

Structures, partial classes are

supported by .net.

Platform
independency

Java is fully platform

independent. That means Java
program works on any
operating system, like
Windows, Mac, Solaris, LINUX,
Android, iOS etc.

Prior to .NET 4.6, it was �platform

independent� with support of some
third party tools such as �Mono�.

From .NET 4.6 onwards, .NET is

�platform independent�, which
supports many operating systems such
as Windows, Mac, LINUX, Android and
iOS etc.
Versions of .NET

Versions of .NET

Sl.
No

.NET Framework

Year of
release

Concepts

.NET Framework 1.0

2002

Console Apps,

Basics,

OOP,

WinForms,

Web Forms,

ADO.NET

.NET Framework 1.1

2003

Bug fixes

.NET Framework 2.0

2005

Improved web controls,

Data controls, Themes and skins,

Master pages,

Partial classes, Nullable types,

Anonymous methods, Generics

4
.NET Framework 3.0

2006

WPF

WCF

.NET Framework 3.5

2007

LINQ

ASP.NET AJAX

.NET Framework 4.0

2010

ADO.NET Entity Framework

Task Parallel Library

ASP.NET Web Pages

ASP.NET MVC

.NET Framework 4.5

2012

Open Authentication

ASP.NET Web API

ASP.NET Bundles and Minification

.NET Framework 4.5.1

2013

Async and Await

.NET Framework 4.5.2

2014

Bug fixes
10

.NET Framework 4.6

2015

.NET Core (open-source and cross-platform).

ASP.NET Core

11

.NET Framework 4.6.1

2015

Bug fixes

12

.NET Framework 4.6.2

2016

Bug fixes

13

.NET Framework 4.7

2017

Improved Performance
.NET Framework (vs) Visual Studio

Types of software of .NET

� �.NET� is a �development platform�, which is provides two software:

1. .NET Framework
2. Visual Studio

1. .NET Framework:
� It is the �Software Development Kit (SDK)�, which provides many
components such as CIL, CLR, FCL, CLS, which is used to develop &
run the .net applications.
� It should be installed in both developer system and user system.
� When we install Visual Studio in the developer system, automatically
.NET Framework will be installed.

2. Visual Studio:
� It is the �code editor�, which is used to write .net programs
(applications).
� It should be installed only in the developer system.
Versions of Visual Studio

Versions of Visual Studio

Visual Studio Version

Year of
Release

Supported Operating Systems

Supported
.NET
Framework
Versions

Visual Studio 2002 (7.0)

2002

Windows 2000

Windows XP

.NET 1.0

Visual Studio 2003 (7.1)

2003

Windows 2000

Windows XP

.NET 1.1

Visual Studio 2005 (8.0)

2005

Windows 2000

Windows XP

.NET 2.0

Visual Studio 2008 (9.0)

2007

Windows 2000

Windows XP

Windows 7

.NET 2.0
.NET 3.0

.NET 3.5

Visual Studio 2010 (10.0)

2010

Windows XP + Service Pack 3

Windows 7

.NET 2.0

.NET 3.0

.NET 3.5

.NET 4.0

Visual Studio 2012 (11.0)

2012

Windows 7

Windows 8.1

Windows 10

.NET 2.0

.NET 3.0

.NET 3.5

.NET 4.0

.NET 4.5

Visual Studio 2013 (12.0)

2013

Windows 7 + Service Pack 1

Windows 8.1

Windows 10

.NET 2.0

.NET 3.0

.NET 3.5

.NET 4.0

.NET 4.5
.NET 4.5.1

Visual Studio 2015 (14.0)

2015

Windows 7 + Service Pack 1

Windows 8.1

Windows 10

.NET 2.0

.NET 3.0

.NET 3.5

.NET 4.0

.NET 4.5

.NET 4.5.1

.NET 4.5.2

.NET 4.6

.NET 4.6.1

.NET 4.6.2
Visual Studio 2017 (15.0)

2017

Windows 7 + Service Pack 1

Windows 8.1

Windows 10

.NET 2.0

.NET 3.0

.NET 3.5

.NET 4.0

.NET 4.5

.NET 4.5.1

.NET 4.5.2

.NET 4.6

.NET 4.6.1

.NET 4.6.2

.NET 4.7
System Requirements of Visual Studio 2015

System Requirements of Visual Studio 2015:

Software /
Hardware

Requirement

Minimum

Recommended

Processor

1.6 Ghz

2.3 Ghz or higher

RAM

1 GB

4 GB or higher

Hard disk free space

on C: drive

12 GB

15 GB or higher

Operating System

Windows 7 + Service Pack 1

Windows 8.1

Windows 10

Windows 10

Internet Explorer

Internet Explorer 10

Internet Explorer 11 or
above
System Requirements of .NET Framework
4.6

System Requirements of .NET Framework:

Software /
Hardware

Requirement

Minimum

Recommended

Processor

1.6 Ghz

2.3 Ghz or higher

RAM

1 GB

2 GB or higher

Hard disk free space

on C: drive

2 GB

4 GB or higher

Operating System

Windows 7 + Service Pack 1

Windows 8

Windows 8.1

Windows 10

Windows 10
Execution Model of .NET Program

.NET programs are compiled and executed as follows:

C:\Users\Harsha\OneDrive\C#.NET\9. .NET Program Execution Model\Compilation and

Execution Model of .NET 2.png
Steps:

1. Programmer: Writes a .net program in any .net language, such as C#.NET,

VB.NET or VC++.NET etc.
2. Programmer: Clicks on "Start" button in visual studio.
3. Visual Studio: Calls the respective language compiler. Every .net language
has its own compiler. Ex: C#.NET compiler is �csc�; VB.NET compiler is �vbc�.
For example, the programmer has written c#.net program; then it calls
"C#.NET Compiler".
4. Compiler: The compiler converts the program (source code) into "Microsoft
intermediate language" (MSIL). The compiler stores the MSIL code in a file
called �.EXE� file (Executable file).
5. Visual Studio: Visual Studio calls "CLR (Common Language Runtime)" and
gives MSIL code to it.
6. CLR: CLR converts the program from MSIL language to �native machine
language� (based on the current operating system).
7. Processor: Processor executes the native machine code.
. CIL or MSIL is the intermediate language, developed by Microsoft Corporation,
for .NET.
. The .net programs are converted into �MSIL language� first; and then converted
into �native machine language�.
. The MSIL code will be stored in "EXE" file. Ex: filename.exe. The �native
machine language� code will not be saved in any file, it directly runs.
. Once the code is converted into MSIL, it doesn't matter in which .net language
it is originally developed. So for all .net languages, we can have a common
runtime engine called "CLR".

CIL (or) MSIL

CIL (Common Intermediate Language)

[or]

MSIL (Microsoft Intermediate Language)

.NET Framework Architecture

.NET Framework Architecture

� �.NET framework� is a SDK (Software Development Kit), which is divided as

several components.
� �.NET Framework Architecture� explains the list of components of .NET
Framework, and how they are arranged internally.
Explanation:

� "Windows" operating system works based on "processor".

� "CLR" works based on "Windows Operating System".
� "BCL" works based on "CLR".
� "ADO.NET" works based on "BCL".
� "WinForms", "ASP.NET", and �Other Frameworks� work based on "ADO.NET"
and "BCL".
� "CLS" is created based on "WinForms", "ASP.NET" and �Other Frameworks�.
� "C#.NET", "VB.NET", "Other Languages" are developed based on "CLS".
� Finally, the programmers are writing the programs by using the languages
called �C#.NET, �VB.NET� etc.
. CLR stands for �Common Language Runtime�.
. CLR is the �Execution Engine� or �Execution Environment� of .NET.
. To run any type of .net program (app), CLR must be installed in the computer.
. CLR will be started automatically when the .net application execution starts.
CLR performs essential tasks internally, while running any .net application.
. Without CLR, we can�t run any .net program.
. CLR reads the �MSIL code� from the EXE file, converts the same into �native
machine code�, gives the same to the operating system and then operating
system executes the native machine code; then the user gets the output. So
CLR is helps the operating system while executing the .net program.
. CLR will be installed automatically as a part of �.NET Framework� software. CLR
must be installed in both developer�s machine and user�s machine.
. CLR has the following inner components (sub components).

CLR

CLR (Common Language Runtime)

Sub Components of CLR

1. Memory Manager: �Memory Manager� is a sub component in CLR, which

allocates memory (in RAM) for the variables and objects in the program.
2. Garbage Collector: �Garbage Collector� is a sub component in CLR, which
deletes the variables and objects that are created during the program,
automatically at the end of the program execution.
3. Class Loader: �Class Loader� is a sub component in CLR, which loads a class
on-demand. When we try to access a class in the program for the first time,
then the �Class Loader� searches for the class in the entire program, loads
the class into the memory, and it passes the class to JIT compiler. That
means if we don�t call a class, it will not be loaded into memory. This avoids
un-necessary loading of the classes, if we don�t require them. So it improves
performance.
4. JIT (Just-In-Time) Compiler: �JIT Compiler� is a sub component in CLR,
which converts the �MSIL code� into �native machine language� (based on
current operating system).
5. Thread Manager: �Thread Manager� is a sub component in CLR, which
manages the threads of the program. It gives necessary instructions to the
processor, which thread is to be executed when. A thread is a "part of the
program" or "background work".
6. Exception Manager: �Exception Manager� is a sub component in CLR, which
passes necessary instructions to the operating system, which code should be
executed when an exception (runtime error) occurs while executing the
program.
7. Security Manager: �Security Manager� is a sub component in CLR, which
takes care about different types of security in .net such as windows
authentication, forms authentication, open authentication etc.
C:\Users\Harsha\Dropbox\C#.NET\19. CLR\CLR Architecture.png
. �CLS� is the set of rules, based on which all .net languages (C#.NET, VB.NET,
VC++.NET etc.) are developed.
. The common rules are about literals, operators, identifiers, data types, type
conversion, object oriented programming etc.

CLS

CLS (Common Language Specification)

. �CTS� is a set common data types, based on which, the data types of all .net
languages (C#.NET, VB.NET, VC++.NET etc.) are developed.
. Thus, we achieve the uniform data types among all .net languages.
. The following is the list of data types of CTS:
1. SByte
2. Byte
3. Short
4. UShort
5. Int32
6. UInt32
7. Int64
8. UInt64
9. Single
10. Double
11. Decimal
12. Char
13. String
14. Boolean
15. DateTime

CTS

CTS (Common Type System)

. .NET provides a set of libraries, based on which we can develop .net
applications.
. FCL is divided into the following parts:

FCL

FCL (Framework Class Library)

1. BCL: BCL is a set of library files, which can be used in all types of
applications.
2. WinForms: This is a set of library files, which can be used only in windows
applications.
3. ASP.NET: This is a set of library files, which can be used only in web
applications.
4. ADO.NET: This is a set of library files, which can be used in all types of
applications for connecting to databases.
C#.NET � Language Fundamentals
Introduction to C#.NET

What is C#.NET:

C#.NET is the .NET�s most popular programming language, which is

used to create console, windows applications primarily. However, it can
be used in combination of ASP.NET, for development of web
applications.

� C#.NET is advanced than C, C++.

� C#.NET is an �Object Oriented Programming Language�.
� C#.NET is a case sensitive language.
� C#.NET is an advanced and matured language.
� C#.NET is a high-level programming language.
� C#.NET is a compiler-based language.
� C#.NET is a part of .NET Framework.
� C#.NET programs run based on the .NET run time environment.
Versions of C#.NET

Sl.
No

C#.NET
Version

.NET Framework Version

Year of
release

C#.NET 1.0

.NET Framework 1.0

2002

C#.NET 1.1

.NET Framework 1.1

2003

C#.NET 2.0

.NET Framework 2.0

2005

C#.NET 3.0

.NET Framework 3.0

2006

C#.NET 3.5

.NET Framework 3.5

2007

C#.NET 4.0

.NET Framework 4.0

2010

C#.NET 5.0

.NET Framework 4.5

2012

C#.NET 5.1

.NET Framework 4.5.1

2013

C#.NET 5.2

.NET Framework 4.5.2

2014

10

C#.NET 6.0

.NET Framework 4.6

2015

12

C#.NET 7.0

.NET Framework 4.6.2

2016
Project and Solution

Project

� Project is a folder, which is a �group of files�.

� A file contains code (program).
� When we compile the project, Visual Studio generates only one EXE file for
the entire project, which contains the compiled source code (in MSIL
language) of all the files of the same project.

Solution

� Solution is a folder, which is a �group of projects�.

File Types of .NET

File Types of .NET

� .NET supports the following file types:

File
Extension

Full form

Description

.cs

C# file

A C# file contains the C#.NET program

(source code).

.vb

VB file

A VB file contains the VB.NET program

(source code).

.csproj

C# Project

A project is a collection of files.

The project file contains the list of all the

files in the current project.

.sln

Solution

A solution is a collection of projects.

The solution file contains the list of all the

projects in the current solution.

.exe

Executable file

The EXE file contains the compiled source

code of a project. For every project, a
separate EXE file will be created.

.config

Configuration File
The configuration file contains the
configuration settings of a project.
Folder Structure of .NET Program

Folder Structure of .NET Program

� .NET program (project) should have the following folder structure.

� Every solution is a folder.
� Every project is folder.

Solution Folder

. Project Folder
o filename.cs
o App.config
o projectname.csproj
o bin\projectname.exe

. solutionname.sln
Tokens of C#.NET

Tokens of C#.NET

� In "C#.NET", we have to use the following tokens (parts of the language).

Sl.
No

Token

Description

Literals

Fixed values are literals.

� Integer literals: Any number without decimal part.

Ex: 10
� Floating-point literals: Any number with decimal
part. Ex: 10.87
� Character literals: Any single character in single
quotes. Ex: �A�.

The character can be alphabet, digit, space or special

symbol.

� String literals: Any one or more characters in double

quotes. Ex: �Abc 123$�

Operators

Any symbols such as +, -, *, /, %, =, == etc.

Keywords

void, if, switch, case, break, continue, goto, while, do, for,
return, int, float, double, decimal, string, throw, try, catch,
finally etc.

Identifiers

Any user-defined names: abc

Console Application Development in C#.NET

Console Application Development in C#.NET

� Console applications are the programs that run on �Command Prompt�

window.
� Console applications support CUI (Character User Interface).
� In console applications, all the input and output will be in the form of
characters only.
� Console applications are not user-friendly.
� Console applications are not used in real time, but good for learning
programming basics and OOP concepts.
Console Application Development

In C#.NET - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �Project1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �Solution1�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Class1

static void Main()

System.Console.Write(10);

System.Console.Write(10.729);

System.Console.Write('A');

System.Console.Write("abc");

System.Console.Write(true);

System.Console.Write(false);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
I/O Statements in C#.NET

List of I/O statements in C#.NET

� C#.NET provides the following statements for performing I/O operations in

console applications. That means we can show output to the user and accept
input from the user, using I/O statements.
1. System.Console.Write()
2. System.Console.WriteLine()
3. System.Console.ReadKey()
4. System.Console.ReadLine()
5. System.Console.Clear()

1. System.Console.Write()

� This statement is used to display the given value on the command prompt
window.
� After printing the value, the cursor will be kept in the same line.
� Syntax: System.Console.Write(value);
� Example: System.Console.Write(100);

2. System.Console.WriteLine()

� This statement is used to display the given value on the command prompt
window.
� After printing the value, the cursor will be automatically moved to the next
line.
� Syntax: System.Console.WriteLine(value);
� Example: System.Console.WriteLine(100);
3. System.Console.ReadKey()

� This statement is used to wait until the user presses any key on the
keyboard.
� Syntax: System.Console.ReadKey();
� Example: System.Console.ReadKey();

4. System.Console.ReadLine()

� This statement is used to accept a string value from keyboard.

� Syntax: System.Console.ReadLine();
� Example: System.Console.ReadLine();

5. System.Console.Clear()

� This statement is used to clear the screen.

� Syntax: System.Console.Clear();
� Example: System.Console.Clear();
System.Console.WriteLine � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �WriteLineExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �WriteLineExample�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

System.Console.WriteLine("Hello");

System.Console.WriteLine("Hello");

System.Console.WriteLine("Hello");

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
System.Console.ReadKey �

Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ReadKeyExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ReadKeyExample�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

//display message

System.Console.WriteLine("Hello");

//wait for pressing any key on the keyboard

System.Console.ReadKey();

//display message

System.Console.WriteLine("Hello");

//wait for pressing any key on the keyboard

 System.Console.ReadKey();

//display message

System.Console.WriteLine("Hello");

//wait for pressing any key on the keyboard

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Press Enter.

Press Enter.
System.Console.Clear - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ClearExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ClearExample�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

//display message

System.Console.WriteLine("Hello");

//wait for pressing any key on the keyboard

System.Console.ReadKey();

//clear the screen

System.Console.Clear();

//display message

System.Console.WriteLine("how");
 //wait for pressing any key on the keyboard

System.Console.ReadKey();

//clear the screen

System.Console.Clear();

//display message

System.Console.WriteLine("are you");

//wait for pressing any key on the keyboard

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Press Enter.

Press Enter.
Variables in C#.NET

Variables

� A variable is a named memory location in RAM, to store a particular type of

value temporarily while the program is running.
� All the variables stored in RAM (temporary memory).
� All the variables must be declared before its usage. While declaring
variables, data type is to be specified. Based on the data type, the amount
of memory to be allocated will be decided. Once a variable is declared, we
can�t change the �variable name� or �variable�s data type�.
� The variables memory will be allocated when the program execution starts;
and all the variables will be deleted (de-allocated) from memory
automatically, at the end of the program.
� A variable can store only one value. If you assign another value, the old value
will be overwritten.
� We can change the value of a variable any no. of times.
� Syntax to create a variable:

datatype variablename ;

� Syntax to set value into a variable:

variablename = value ;

� Syntax to get the value of a variable:

variablename

Variable Naming Rules

You must follow the below rules while giving name for variables.

� Variable names should not have spaces.

� Variable names should not have special characters except under score (_).
� Duplicate variable names not allowed in the method.
� Variable names can�t be same as keyword.
Variables - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �VariablesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �VariablesExample�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

//create a variable

int x;

//set value into the variable

x = 10;

//get the value of variable

System.Console.WriteLine(x);

//wait for pressing any key on the keyboard

System.Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Data Types in C#.NET

Data Type

� A data type is a concept, which specifies the type of the data that is to be
stored in a variable.

Types of Data types

� Data types are two types:

I. Numerical data types
II. Non-numerical data types
Numerical Data Types in C#.NET

Numerical Data Types

Sl.
No

Data
Type

Description

No.
of
Bytes

Range

Suitable to
store

sbyte

8-bit signed
integer

1
byte

-128 to 127

Very small
positive or
negative
integers

byte

8-bit
unsigned
integer

1
byte

0 to 255

Very small
positive
integers

short
16-bit
signed
integer

2
bytes

-32,768 to 32,767

Small
positive or
negative
integers

ushort

16-bit
unsigned
integer

2
bytes

0 to 65,535

Small
positive
integers

int

32-bit
signed
integer

4
bytes

-2,147,483,648 to 2,147,483,647

Medium
positive or
negative
integers

uint

32-bit
unsigned
integer

4
bytes

0 to 4,294,967,295

Medium
positive
integers

long

64-bit
signed
integer

8
bytes

-9,223,372,036,854,775,808 to

9,223,372,036,854,770,000

Large
positive or

negative
integers

ulong

64-bit
unsigned
integer

8
bytes

0 to 18,446,744,073,709,551,615

Large
positive
integers

float

Signed
floating-
point
number

4
bytes

-3.402823E+38 to 3.402823E+38
(Precision: 7 digits)

Small
floating-
point
numbers
10

double

Signed
floating-
point
number

8
bytes

-1.79769313486232E+308 to
1.79769313486232E+308
(Precision: 15 digits)

Medium
floating-
point
numbers

11

decimal

Signed
floating-
point
number

16
bytes

-79228162514264337593543950335
to
79228162514264337593543950335
(Precision: 28 digits)

Large
floating-
point
numbers

Default Numerical data types

� C# compiler automatically treats a �number without decimal part� as �int�

data type, if it is within the maximum limit of �int� data type.
� C# compiler automatically treats a �number without decimal part� as �long�
data type, if it exceeds the limit of �int� data type.
� C# compiler automatically treats a number with decimal part as �double�
data type.
Numerical Data Types - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �NumericalDataTypesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NumericalDataTypesExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variables for all numerical data types

sbyte a = 10;

byte b = 20;

short c = 30;

ushort d = 40;

int e = 50;

uint f = 60;

long g = 70;

ulong h = 80;

float i = 90.23F;

double j = 100.23489;

decimal k = 110.882932M;

//displays the values of all variables

System.Console.WriteLine(a);
 System.Console.WriteLine(b);

System.Console.WriteLine(c);

System.Console.WriteLine(d);

System.Console.WriteLine(e);

System.Console.WriteLine(f);

System.Console.WriteLine(g);

System.Console.WriteLine(h);

System.Console.WriteLine(i);

System.Console.WriteLine(j);

System.Console.WriteLine(k);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
MinValue and MaxValue

NumericalDataType.MinValue

� This statement returns the minimum value of the specified numerical data
type.
� Syntax: datatype.MinValue
� Ex: int.MinValue

NumericalDataType.MaxValue

� This statement returns the maximum value of the specified numerical data
type.
� Syntax: datatype.MaxValue
� Ex: int.MaxValue
MinValue and MaxValue - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MinValueMaxValueExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MinValueMaxValueExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//get the minimum value of "int" data type

int min = int.MinValue;

//get the maximum value of "int" data type

int max = int.MaxValue;

//display the min and max values

System.Console.WriteLine(min);

System.Console.WriteLine(max);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Non-Numerical Data Types in C#.NET

Non-Numerical Data Types

Sl.
No

Data
Type

Description

Value format

No. of Bytes

char

To store single
character

�character�

2 bytes

string

To store one or more

characters.

Max: 2 billion
characters

"string here"

No. of characters * 2

bool

To store true / false

values.

true or false

1 byte

DateTime

To store date and time

values.
M/d/yyyy hh:mi:ss:ms

8 bytes
char - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �charExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �charExample�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

//create variable of "char" data type

char ch = 'A';

//display the value of the variable

System.Console.WriteLine(ch);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String in C#.NET

String

� String: A string is a group of characters.

� String literal should be written inside the double quotes.
� All the names are strings. Ex: person names, city names, country names etc.
� String may contain alphabets, numbers, spaces and also special symbols.
� Alpha-numerical values are also treated as strings. Ex: car number, phone
number, bank ifsc codes etc.
� Syntax to create a string variable:
o string variablename = "value";
String - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StringExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StringExample�. Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

//create a variable

string s = "Hello 123 $#&";

//display the value of the variable

System.Console.WriteLine(s);

System.Console.WriteLine(s);

System.Console.WriteLine(s);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Bool in C#.NET

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �boolExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �boolExample�.
� Click on OK.
� It shows �Program.cs� file automatically.
� Type the following code for �Program.cs� file:

Program.cs

class Program

static void Main()

//create variable of "bool" data type

bool b = true;

//display the value of the variable

System.Console.WriteLine(b);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Operators in C#.NET

What is Operator:

� Operator is a symbol to perform an operation.

� An operator receives one or two operands and perform some operation &
returns the result.
� Types of operators:
1. Arithmetical Operators
2. Assignment Operators
3. Increment and Decrement Operators
4. Relational Operators
5. Logical Operators
6. Concatenation Operator
7. Conditional Operator
Arithmetical Operators in C#.NET

Arithmetical Operators

Sl. No

Operator

Description

Addition

Subtraction

Multiplication

Division

Remainder
Arithmetical Operators - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArithmeticalOperatorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArithmeticalOperatorsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create two variables of "double" data type

double a = 10, b = 3;

//addition

double c = a + b;

//subtraction

double d = a - b;

//multiplication

double e = a * b;

//division

double f = a / b;
 //remainder

double g = a % b;

//display all the values

System.Console.WriteLine(a); //Output: 10

System.Console.WriteLine(b); //Output: 3

System.Console.WriteLine(c); //Output: 13

System.Console.WriteLine(d); //Output: 7

System.Console.WriteLine(e); //Output: 30

System.Console.WriteLine(f); //Output: 3.3333333333

System.Console.WriteLine(g); //Output: 1

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Assignment Operators in C#.NET

Assignment Operators

Sl. No

Operator

Description

Assigns to

+=

Add and assigns to

-=

Subtract and assigns to

*=

Multiply and assigns to

%=

Remainder and assigns to

Assignment Operators - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AssignmentOperatorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AssignmentOperatorsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create two variables of "int" data type

int a = 100;

int b;

//get the value from "a" and set the same into "b"

b = a;

//display the values of "a" and "b"

System.Console.WriteLine(a); //Output: 100

System.Console.WriteLine(b); //Output: 100

//a = a + 10

a += 10;

System.Console.WriteLine(a); //Output: 110

 //a = a - 10

a -= 10;

System.Console.WriteLine(a); //Output: 100

//a = a * 3

a *= 3;

System.Console.WriteLine(a); //Output: 300

//a = a / 3

a /= 3;

System.Console.WriteLine(a); //Output: 100

//a = a % 30

a %= 30;

System.Console.WriteLine(a); //Output: 10

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Increment / Decrement Operators in C#.NET

Increment / Decrement Operators

Sl. No

Operator

Description

++

Increment

--

Decrement
Increment / Decrement Operators - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IncDecOperatorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IncDecOperatorsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create a variable of "int" data type

int n = 10;

//display the value of "n"

System.Console.WriteLine(n); //Output: 10

//n = n + 1

n++;

System.Console.WriteLine(n); //Output: 11

//n = n - 1

n--;

System.Console.WriteLine(n); //Output: 10
 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Relational Operators in C#.NET

Relational Operators

Sl. No

Operator

Description

==

Equal to

!=

Not equal to

<

Less than

>

Greater than

<=

Less than or equal to

>=

Greater than or equal to

Relational Operators - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �RelationalOperatorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �RelationalOperatorsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create two variables of "long" data type

long x = 1000, y = 2000;

//check whether x and y are equal

bool b1 = (x == y);

//check whether x and y are not equal

bool b2 = (x != y);

//check whether x is less than y

bool b3 = (x < y);

//check whether x is greater than y

bool b4 = (x > y);

 //check whether x is less than or equal to y

bool b5 = (x <= y);

//check whether x is greater than or equal to y

bool b6 = (x >= y);

System.Console.WriteLine(b1); //Output: false

System.Console.WriteLine(b2); //Output: true

System.Console.WriteLine(b3); //Output: true

System.Console.WriteLine(b4); //Output: false

System.Console.WriteLine(b5); //Output: true

System.Console.WriteLine(b6); //Output: false

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Logical Operators in C#.NET

Logical Operators

Sl. No

Operator

Description

&&

And (Both conditions must be true)

||

Or (Any one of the conditions must be true)

Not (Given condition will be reverse)

Logical Operators - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �LogicalOperatorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LogicalOperatorsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create 3 variables of "int" data type

int a = 10, b = 20, c = 10;

//and

bool result1 = ((a == b) && (b > c));

System.Console.WriteLine(result1); //Output: false

//or

bool result2 = ((a == b) || (b > c));

System.Console.WriteLine(result2); //Output: true

//not

bool result3 = !(a == b);

System.Console.WriteLine(result3); //Output: true

 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Concatenation Operator in C#.NET

Concatenation Operator

Sl. No

Operator

Description

Concatenation. It attaches two values and returns as a

string. The following cases, "+" operator is
"concatenation operator".

� String + String
� String + Number
� Number + String
Concatenation Operator - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConcatenationOperatorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConcatenationOperatorExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create strings

string s1 = "peers";

string s2 = "tech";

string s3;

//concatenate s1 and s2 and store the result in s3

s3 = s1 + s2;

System.Console.WriteLine(s1); //Output: peers

System.Console.WriteLine(s2); //Output: tech

System.Console.WriteLine(s3); //Output: peeerstech

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Conditional Operator in C#.NET

Conditional Operator

Sl.
No

Operator

Description

(condition)? value1 : value2

Checks the given condition.

Returns the value1, if given condition is TRUE

Returns the value2, if the given condition is

FALSE.
Conditional Operator - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConditionalOperatorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConditionalOperatorExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create a variable of "int" data type

int n = -100;

//check the condition; store "positive" if the condition is true; store

"negative" if the condition is false

string s = ( (n >= 0) ? "positive" : "negative");

System.Console.WriteLine(s); //Output: negative

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Control Statements in C#.NET

What are control statements?

� Control statements are used to control the �program execution flow�.

� That means these are used to �go forward� or �go backward� within the
program.

Types of control statements:

. Conditional Control Statements

� If
� Switch-case

. Looping Control Statements

� While
� Do-While
� For

. Jumping Control Statements

� Break
� Continue
� Goto
If in C#.NET

If

Sl.
No

Control
Statement

Syntax

Description

If

if (condition)

Your code here

It executes the �if block� only if the

given condition is TRUE.

It doesn�t execute anything if the

given condition is FALSE.

If-Else

if (condition)

Your code here

else

Your code here

It executes the �if block� if the

given condition is TRUE.

It executes the �else block� if the

given condition is FALSE.
3

Else-If

if (condition)

Your code here

else if (condition)

Your code here

else if (condition)

Your code here

else

Your code here

It executes the �if block�, if the

�first condition� is TRUE.

It executes the "first else if block",

if the second condition is TRUE.

It executes the "second else if

block", if the third condition is
TRUE.

It executes the �else block� if all

the conditions are FALSE.
4

Nested If

if (condition)

if (condition)

Your code here

else

Your code here

else

if (condition)

Your code here

else

Your code here

If inside another if.

If - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IfExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IfExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variables

int n = 100;

//check whether n is equal to 100

if (n == 100)

System.Console.WriteLine("n is equal to 100");

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
If � Else - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IfElseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IfElseExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variables

int n = 150;

//check whether n is equal to 100

if (n == 100)

System.Console.WriteLine("n is equal to 100");

else

System.Console.WriteLine("n is not equal to 100");

System.Console.ReadKey();

}
}

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Else � If - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ElseIfExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ElseIfExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variables

int a = 10, b = 20;

//check which is the big number

if (a == b)

System.Console.WriteLine("a and b are equal");

else if (a > b)

System.Console.WriteLine("a is bigger than b");

else

System.Console.WriteLine("b is bigger than a");

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Nested If - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �NestedIfExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NestedIfExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variables

int a = 150, b = 100;

string msg;

//outer if

if (a >= b)

//inner if

if (a > b)

msg = "a is greater than b";

//"else" for "inner if"

else

msg = "a is equal to b";

 }

//"else" for "outer if"

else

msg = "a is less than b";

System.Console.WriteLine(msg); //Output: a is greater than b

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Switch � Case in C#.NET

Switch-case

Sl.
No

Control
Statement

Syntax

Description

Switch-
case

switch (variable)

case value1 : your code here ; break;

case value2 : your code here ; break;

default: your code here ; break;

It checks the
variable�s value
whether it matches
with which case &
executes the
corresponding code.

It executes the
default code if all
cases are not
matched.
Switch � Case - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SwitchCaseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SwitchCaseExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variables

int monthnumber = 7;

string monthname;

//check the value of monthnumber whether it matches with any one of

the following cases

switch (monthnumber)

case 1: monthname = "Jan"; break;

case 2: monthname = "Feb"; break;

case 3: monthname = "Mar"; break;

case 4: monthname = "Apr"; break;

case 5: monthname = "May"; break;

case 6: monthname = "Jun"; break;

case 7: monthname = "Jul"; break;

 case 8: monthname = "Aug"; break;

case 9: monthname = "Sep"; break;

case 10: monthname = "Oct"; break;

case 11: monthname = "Nov"; break;

case 12: monthname = "Dec"; break;

default: monthname = "unknown"; break;

System.Console.WriteLine(monthname); //Output: Jul

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
While in C#.NET

while

Sl.
No

Control
Statement

Syntax

Description

While

while (condition)

your code here

It executes the code repeatedly, while

the condition is TRUE.

If exits from the loop automatically when

the condition is FALSE.
While - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �WhileExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �WhileExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//initialization

int i = 1;

//condition

while (i <= 10)

System.Console.WriteLine(i);

i++; //incrementation

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Do � While in C#.NET

do-while

Sl.
No

Control
Statement

Syntax

Description

Do-While

do

Your code here

} while( condition );

It repeats the code execution while the

condition is TRUE.

It executes the code at least once. That

means it will not check the condition for
the first iteration.

If exit from the loop automatically when

the condition is FALSE.
Do � While - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DoWhileExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DoWhileExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//initialization

int i = 1;

do

System.Console.WriteLine(i);

i++; //incrementation

} while (i <= 10); //condition

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
For in C#.NET

for

Sl.
No

Control
Statement

Syntax

Description

For

for (initialization ; condition ; iteration )

Your code here

Initialization,
condition, iteration
(increment or
decrement) are
written in a single
line; so that it is easy
to understand.
For - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ForExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ForExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//initialization; condition; incrementation

for (int i = 1; i <= 10; i++)

System.Console.WriteLine(i);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Break in C#.NET

break

Sl.
No

Control
Statement

Syntax

Description

Break

break;

It terminates (stops) the loop.

Break - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �BreakExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �BreakExample�. Click on OK.

Program.cs

class Program

static void Main()

//initialization; condition; incrementation

for (int i = 1; i <= 10; i++)

System.Console.WriteLine(i);

if (i == 6)

break; //stop the loop when "i" value is reached to "6".

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Continue in C#.NET

continue

Sl.
No

Control
Statement

Syntax

Description

Continue

continue;

It skips the current iteration and jumps to the next

iteration.
Continue - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ContinueExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ContinueExample�. Click on OK.

Program.cs

class Program

static void Main()

//initialization; condition; incrementation

for (int i = 1; i <= 10; i++)

if (i == 6)

continue; //skip "6" and go to "7"

System.Console.WriteLine(i);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Goto in C#.NET

goto

Sl.
No

Control
Statement

Syntax

Description

Goto

goto LabelName;

It jumps to the specified label, within the

same method.
Goto - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �GotoExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �GotoExample�.
� Click on OK.

Program.cs

class Program

static void Main()

System.Console.WriteLine("one");

System.Console.WriteLine("two");

//jump to mylabel

goto mylabel;

System.Console.WriteLine("three");

System.Console.WriteLine("four");

System.Console.WriteLine("five");

//mylabel starts here

mylabel:

System.Console.WriteLine("six");

System.Console.WriteLine("seven");
 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Nested For Loops in C#.NET

Syntax of Nested For Loop

Description

for (initialization; condition; iteration)

for (initialization; condition; iteration)

Your code here

The �inner for loop� executes �n�

no. of times, while the condition
outer for loop�s condition is true.
Nested For Loops in C#.NET - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �NestedForLoopsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NestedForLoopsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//outer loop (5 times)

for (int i = 1; i <= 5; i++)

//inner loop (10 times)

for (int j = 1; j <= 10; j++)

System.Console.Write(j);

System.Console.Write(", ");

System.Console.WriteLine();

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods in C#.NET

Methods

. A method is a set of instructions (statements) to perform a particular task.

. A method is a �re-usable code block�.
. Methods are used to divide the large code as small units.
. Methods improve the understandability of the program.
. Every method should have a name.
. Methods can be called any no. of times.
. Methods can be created and called in any order.
. Arguments: The value that are passed from calling portion to the method
definition are called arguments or parameters. The data type of argument is
called �argument type�. Every argument can be different type.
. Return Value: The value that is passed from method definition to the
calling portion is called �return value�. A method can return only one value
maximum. The data type of return value is called �return type�. If a method
doesn�t return any value, its return type should be said as �void�.
. Method can be created inside the class only. A class is a collection of
methods. We will understand the �classes� deeply in later topics.
. �Static methods� (methods that are declared as �static�) can be called
without creating any object for the class. We will understand more about
"static" in the later chapters.
Syntax of creating a method

public static ReturnType Methodname (DataType1 ArgumentVariable1,

DataType2 ArgumentVariable2, �)

Your code here

return (value );

}
Methods � Simple Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodsSimpleExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodsSimpleExample�.
� Click on OK.

Program.cs

class Program

//create a method called "City" in "Program" class

static void City()

System.Console.WriteLine("Hyderabad");

static void Main()

//call "City" method of "Program" class

City();

//call "City" method of "Program" class

City();

//call "City" method of "Program" class

City();
 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods � Complex Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodsComplexExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodsComplexExample�.
� Click on OK.

Program.cs

class Program

//create a method called "City" in "Program" class

static void City()

//display message

System.Console.WriteLine("Hyderabad");

//call "Country" method from "City" method

Country();

//create a method called "Country" in "Program" class

static void Country()

//display message

System.Console.WriteLine("India");

}
 static void Main()

System.Console.WriteLine("Message from Main");

//call "City" method of "Program" class

City();

//call "Country" method of "Program" class

Country();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Arguments and Return - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArgumentsAndReturnExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArgumentsAndReturnExample�.
� Click on OK.

Program.cs

class Program

//create a method called "Add".

public static int Add(int a, int b)

int c; //local variable

c = a + b;

return (c);

static void Main()

//call "Add" method

System.Console.WriteLine(Add(10, 20));

//call "Add" method

System.Console.WriteLine(Add(50, 30));

System.Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Scope of Variables

Scopes of Variables

. �Life time� of the variable is called as �scope�.

. C#.NET supports three scopes:
1. Local variables:
. Declared inside a method.
. Accessible within the same method only.

2. Block level variables:

. Declared inside a block. Ex: if block, for block etc.
. Accessible within the same block only.

3. Class level variables:

. Declared inside a class.
. Accessible within all the methods of same class.
Default Arguments in C#.NET

Default Arguments (or) Optional Parameters

. �Default arguments� concept is used to specify a �default value� for a

�argument�.
. While calling the method, if you don�t supply a value for the parameter, then
the default value will be assigned to the parameter automatically.
. If you supply a value for the parameter, then the given value will be
assigned to the parameter, as usual.

Syntax of method with Default Arguments

public static MethodName (DataType1 ArgumentVariable1 = DefaultValue1,

DataType2 ArgumentVariable2 = DefaultValue2, �)

Your Code here

}
Default Arguments - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �DefaultArgumentsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DefaultArgumentsExample�.
� Click on OK.

Program.cs

class Program

public static void Display(int n = 10)

System.Console.WriteLine("n value is " + n);

static void Main()

Display(50); //Output: 50

Display(100); //Output: 100

Display(); //Output: 10

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Named Parameters in C#.NET

Named Parameters (or) Named Arguments

. �Named parameters� concept allows the programmer to pass a value, based

on the �parameter name�, instead of depending on the order of arguments,
while calling a method.
. Advantage: We can change the order of parameters.
. Syntax:

MethodName(ParameterName : value, ParameterName : value,

�)
Named Parameters - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �NamedParametersExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NamedParametersExample�.
� Click on OK.

Program.cs

class Program

//Display method receives "x" and "y" values as arguments

public static void Display(int x, int y)

//display the value of "x"

System.Console.WriteLine("x is: " + x);

//display the value of "y"

System.Console.WriteLine("y is: " + y);

static void Main()

//call Display method. Pass "10" to "y" and "20" to "x"

Display(y: 10, x: 20); //Output: x is 20, y is 10

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods Overloading in C#.NET

Method Overloading

. �Method Overloading� concept is �writing multiple methods with same

name within the same class, with different types of arguments�.
. The difference can be in data types of arguments or in no. of arguments.
. When you call a method, it calls the method, which matches with the given
arguments.
. Example:
. Method1()
. Method1(int a)
. Method1(double d)
. Method1(int a, double d)
. Method1(double d, int a)
. Method1(string s)

etc.
Methods Overloading - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodOverloadingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodOverloadingExample�.
� Click on OK.

Program.cs

class Program

//method 1

public static void Display(int n)

System.Console.WriteLine("int: " + n);

//method 2

public static void Display(string s)

System.Console.WriteLine("string: " + s);

static void Main()

int a = 100;

string b = "hello";
 Display(a); //calls method1

Display(b); //calls method2

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Types of parameters in C#.NET

Types of Parameters

1. Call by value
2. Call by reference
3. Call by output

Call by Value

. The changes made to the �argument variable� will not be effected in

�original variable�.
. This is default in c#.net.

Call by Reference

. The changes made to the �argument variable� will be effected automatically

in the �original variable�.
. This is implemented using �ref� keyword with �original variable� and
�argument variable�.
. The �original variable� should be a variable (can�t be a literal).

Call by Output

. This is same as �call by reference�.

. The difference between �call by reference� and �call by output� is: the value
of �original variable� will not be transferred to the �argument variable�; but
the value comes back from �argument variable� to �original variable�, at the
end of method.
. The �argument variable� will be �unassigned� by default.
. The �argument variable� must be set to a value before the method
definition ends.
. This is implemented using �out� keyword in both calling portion and
receiving portion.
. The �original variable� should be a variable; can�t be a literal.
Call by value - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �CallByValueExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CallByValueExample�.
� Click on OK.

Program.cs

class Program

//call by value

public static void Method1(int x)

System.Console.WriteLine(x); //Output: 100

x = 150;

System.Console.WriteLine(x); //Output: 150

static void Main()

int a = 100;

Method1(a);

System.Console.WriteLine(a); //Output: 100

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Call by reference - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CallByReferenceExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CallByReferenceExample�.
� Click on OK.

Program.cs

class Program

//call by value

public static void Method1(ref int x)

System.Console.WriteLine(x); //Output: 100

x = 150;

System.Console.WriteLine(x); //Output: 150

static void Main()

int a = 100;

Method1(ref a);

System.Console.WriteLine(a); //Output: 150

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Call by output - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CallByOutExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CallByOutExample�.
� Click on OK.

Program.cs

class Program

//call by value

public static void Method1(out int x)

x = 150;

System.Console.WriteLine(x); //Output: 150

static void Main()

int a;

Method1(out a);

System.Console.WriteLine(a); //Output: 150

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Type Conversion in C#.NET

Type Conversion in C#.NET

� The process of converting a value from �one data type� to �another data
type� is called as �type conversion�.
� C# supports 4 types of type conversion:
1. Implicit Casting
2. Explicit Casting (or) Type Casting
3. Parsing
4. Conversion Methods
Implicit Casting in C#.NET

Implicit Casting

� C# compiler automatically converts a value from �lower numeric data type�

to �higher numeric data type�. This automatic conversion is called �implicit
casting�.
� We will compare the no. of data types of the data type, to identify whether
it is a lower data type / higher data type.
� Ex: �int� to �long�. Here �int� is 4 bytes and �long� is 8 bytes. So it is
�lower�
to �higher�.
� As implicit casting will be performed automatically, there is no syntax for
this. Directly you can assign a value of �lower numeric data type� to �higher
numeric data type�.
Implicit Casting - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ImplicitCastingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ImplicitCastingExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//A variable of "lower numerical data tye" i.e. "short" (2 bytes)

short a = 100;

//A variable of "higher numerical data tye" i.e. "int" (4 bytes)

int b;

//short to int = lower to higher = implicit casting

b = a;

System.Console.WriteLine(a); //Output: 100

System.Console.WriteLine(b); //Output: 100

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Explicit Casting (or) Type Casting in C#.NET

Explicit Casting (or) Type Casting

� It is used to convert a value from �lower numerical data type� to �higher

numerical data type� and also from �higher numerical data type� to �lower
numerical data type�.
� Syntax: (Expected data type)value
Explicit Casting (or) Type Casting - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �TypeCastingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TypeCastingExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variable of "int" data type

int a = 100;

//create variable of "short" data type

short b;

//convert the value from "int" data type "short" data type (higher to
lower), using "type casting" concept

b = (short)a;

System.Console.WriteLine(a); //Output: 100

System.Console.WriteLine(b); //Output: 100

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Parsing in C#.NET

Parsing

. It is used to convert a value from �string� data type to �any numerical data
type�.
. �Parse� is a pre-defined method. Parsing means converting.
. Syntax: NumericalDataTypeName.Parse(value);
. Rule: The string value should contain digits only; otherwise it can�t be
converted into numerical data type.
. Note: If the string value is not convertible into �numerical data type�, you
will get exception (run time error).
Parsing - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ParsingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ParsingExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create variable of "string" data type

string s = "100";

//create variable of "int" data type

int x;

//convert the value from "string" to "int" data type, using Parsing
concept

x = int.Parse(s);

System.Console.WriteLine(s); //Output: 100

System.Console.WriteLine(x); //Output: 100

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
TryParse in C#.NET

TryParse

. When you are converting "alphabets" or "alpha-numeric value" from "string"

data type to "numeric", you will get a run time error (exception).
. "TryParse" is a pre-defined method, which is used to avoid while converting
the value from "string" to "numerical data type".
. It tries to convert the string to numerical data type. If conversion is
successful, it returns "true". If conversion is failed, it returns "false". If
conversion is successful, it stores the result value in the destination variable;
otherwise, it stores 0 (zero) in the destination variable.
. Syntax: bool result = NumericalDataTypeName.TryParse(source
string value, out destination numerical variable);
TryParse - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �TryParseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TryParseExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create string & integer

string s = "1234";

int n;

//try to convert "1234" into "int" data type. If the conversion is

successful, it returns the value into the "out" parameter & "true" directly. If
the conversion is unsuccessful, it returns "false".

bool b = int.TryParse(s, out n);

//display

System.Console.WriteLine(n); //Output: 1234

System.Console.WriteLine(b); //Output: True

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
TryParse � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �TryParseExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TryParseExample2�.
� Click on OK.

Program.cs

class Program

static void Main()

//create string and integer

string s = "hyderabad1234";

int n;

//try to convert "hyderabad1234" into int data type. Actually it not

possible to convert "alphanumeric value" like "hyderabad1234" into "int"
data type. So it returns "0" into "n" and "false" into "b".

bool b = int.TryParse(s, out n);

System.Console.WriteLine(n); //Output: 0

System.Console.WriteLine(b); //Output: False

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Conversion Methods in C#.NET

Conversion Methods

. C#.NET provides a set of conversion methods, which are used to convert a

value from �any standard data type� to �any other standard data type�.
. Standard data types all numerical and non-numerical data types.
. Syntax: System.Convert.MethodName(value);

List of conversion methods

Sl.
No

Conversion Method

Description

byte System.Convert.ToByte(value)

It converts and returns the

given value into �byte� data
type.

sbyte System.Convert.ToSByte(value)

It converts and returns the

given value into �sbyte� data
type.

short System.Convert.ToInt16(value)

It converts and returns the

given value into �short� data
type.

ushort System.Convert.ToUInt16(value)

It converts and returns the

given value into �ushort� data
type.

int System.Convert.ToInt32(value)

It converts and returns the

given value into �int� data type.

uint System.Convert.ToUInt32(value)

It converts and returns the

given value into �uint� data
type.

long System.Convert.ToInt64(value)

It converts and returns the

given value into �long� data
type.

ulong System.Convert.ToUInt64(value)

It converts and returns the

given value into �ulong� data
type.
9

float System.Convert.ToSingle(value)

It converts and returns the

given value into �float� data
type.

10

double System.Convert.ToDouble(value)

It converts and returns the

given value into �double� data
type.

11

decimal System.Convert.ToDecimal(value)

It converts and returns the

given value into �decimal� data
type.

12

char System.Convert.ToChar(value)

It converts and returns the

given value into �char� data
type.

13

string System.Convert.ToString(value)

It converts and returns the

given value into �string� data
type.

14

bool System.Convert.ToBoolean (value)

It converts and returns the

given value into �bool� data
type.

15

DateTime
System.Convert.ToDateTime(value)

It converts and returns the

given value into �DateTime�
data type.
. Note: You have to use the conversion method, based on the destination
data type (target data type), into which you want to convert.
Conversion Methods - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConversionMethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConversionMethodsExample�.
� Click on OK.

Program.cs

class Program

static void Main()

//create a variable of "double" data type

double d = 100;

//create a variable of "int" data type

int n;

//convert the value from "double" data type to "int" data type", using
conversion method

n = System.Convert.ToInt32(d);

System.Console.WriteLine(d); //Output: 100

System.Console.WriteLine(n); //Output: 100

System.Console.ReadKey();

//Note: Try all the remaining conversion methods.

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
C#.NET � Object Oriented
Programming (OOP)
Introduction to Object Oriented
Programming in C#.NET

Introduction of Object Oriented Programming (OOP)

� �Object oriented programming� is a programming style / programming

paradigm, which provides necessary guidelines for the programmers to
write the programs in a well-organized, understandable, secured, re-usable,
efficient, structured, clean, maintainable manner.
� OOP is followed in almost-all modern programming languages such as C++,
VC++, Java, C#.NET, VB.NET etc.
� .NET developers must know OOP.
Objects in C#.NET

Object

� An object represents a real world item. For example, you are an object, your
laptop is an object, and your city is an object.
� An object consists of "details" and "functionality".
� Details are called as "data members" or "fields".
� Functionality is called as "functions" or "methods" or "operations".
� All the objects will be stored in an area called "heap" in RAM.
Data Members and Methods in C#.NET

Data Members

� Data members also called as "details" or "fields".

� The variables inside object are called as "data members".
� Data members are used to store data.

Methods

� Methods also called as "functionality" or "functions" or "operations".

� A method is a "set of statements" to do a particular task in the program.
� Methods are used to manipulate data members.

Example:
Classes in C#.NET

Class

� A class is a "model" or �type� or "blue-print" of object.

� Class is used to define the common members of similar objects.
. For example, there are 10 students. Each student is an object. So 10
students are 10 objects. In each student, we want to store
"studentid", "studentname", "marks". So first we have to create a
class called "Student" and we have to create "studentid",
"studentname", "marks" as members of the "Student" class. Then we
have to create objects based on the class.

� A class specifies the list of data members and methods that you want to
store in every object.
� For a class, memory will not be allocated.
� So you must create an object for the class, in order to access its members.
� Class is a just �model� only; no actual data will be stored in class. Object is
the �real instance�; actual data will be stored in object only.
� Based on a class, any no. of objects can be created.
� When an object is created, the following process happens.
1. Memory will be allocated in RAM (Random Access Memory) for the
object.
2. All the data members of the class will be stored in the object.
3. Data members of the object will be initialized with default values.
. Numerical data members: 0
. Char / string: null
. Bool: false
. DateTime: 1/1/0001 12:00:00 AM

4. Constructor will be called. Constructors will be explained later in this

book.
� All the objects are stored in RAM (temporarily). Objects are created when
the program execution starts. Objects are automatically deleted (erased
from memory) when the program execution ends.
� Each object�s memory will be allocated separately in RAM.

Example:
Reference variables

� A �reference variable� stores address of an object of same class.

� You should store the �address of an object� in the reference variable;
through the reference variable only, we can access the object, in further
statements.
� All reference variables will be stored in an area called "stack" in RAM.

Syntax of creating class

class Classname

Class members here

Syntax of creating a data member in a class:

accessmodifier qualifier datatype datamembername = value;

Syntax of creating a method in a class:

accessmodifier qualifier returntype methodname(arguments)

Code here

Syntax of creating reference

Classname Referencevariablename ;
Syntax of creating object (in heap):

new Classname ( );

Memory allocation of Objects

� All the reference variables are stored in an area called "stack" in RAM. For
every method call, a �stack� will be created automatically.
� All the objects are stored in an area called "heap" in RAM. For entire
application, a �heap� will be created.
� You must store the address of an object into the reference variable;
otherwise you can't access the object.
Object Oriented Programming � Simple
Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �OOPSimpleExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �OOPSimpleExample�.
� Click on OK.

Program.cs

//create a class called "myclass" with 2 data members called "a", "b"; but no
memory allocated as of now.

class myclass

public int a, b;

class Program

static void Main()

//create reference variable (in stack) of "myclass" type

myclass variable1;

//create object (in heap) of "myclass" type and store the object address
in the reference variable called "variable1"

variable1 = new myclass();

//set data into members of first object

variable1.a = 10;
 variable1.b = 20;

//create another reference variable (in stack) of "myclass" type

myclass variable2;

//create another object (in heap) of "myclass" type and store the object
address in the reference variable called "variable2"

variable2 = new myclass();

//set data into members of second object

variable2.a = 30;

variable2.b = 40;

//get data from first object

System.Console.WriteLine(variable1.a);

System.Console.WriteLine(variable1.b);

System.Console.WriteLine("\n");

//get data from second object

System.Console.WriteLine(variable2.a);

System.Console.WriteLine(variable2.b);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Object Oriented Programming � Advanced
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �OOPAdvancedExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �OOPAdvancedExample�.
� Click on OK.

Program.cs

//create a class called "Person" with 2 data members called "name" and
"age"

class Person

//data members

public string name;

public int age;

class Program

static void Main()

//create 2 reference variables of "Person" type

Person p1, p2;

//create 2 objects of "Person" type

 p1 = new Person();

p2 = new Person();

//set data into first object

p1.name = "Scott";

p1.age = 20;

//set data into second object

p2.name = "Allen";

p2.age = 25;

//get data from first object

System.Console.WriteLine("name: " + p1.name);

System.Console.WriteLine("age: " + p1.age);

System.Console.WriteLine("---------------------------------");

//get data from second object

System.Console.WriteLine("name: " + p2.name);

System.Console.WriteLine("age: " + p2.age);

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Console.ReadLine in C#.NET

Reading inputs from keyboard

� To read input values from the user at run time:

o Syntax: string System.Console.ReadLine( )

� It returns the value in �string� data type only. If you want other data types,
you have to use conversion methods.
Console.ReadLine - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ReadLineExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ReadLineExample�.
� Click on OK.

Program.cs

//create a class called "Student" with 3 data members called "studentId",

"studentname" and "marks"

class Student

//data members

public int studentId;

public string studentName;

public int marks;

class Program

static void Main()

//create 3 reference variables of "Student" type

Student s1, s2, s3;

//create 3 objects of "Student" type

s1 = new Student();
s2 = new Student();

s3 = new Student();

//set data into first object

System.Console.Write("Enter first student id: ");

s1.studentId = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter first student name: ");

s1.studentName = System.Console.ReadLine();

System.Console.Write("Enter first student marks: ");

s1.marks = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.WriteLine();

//set data into second object

System.Console.Write("Enter second student id: ");

s2.studentId = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter second student name: ");

s2.studentName = System.Console.ReadLine();

System.Console.Write("Enter second student marks: ");

s2.marks = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.WriteLine();

//set data into third object

System.Console.Write("Enter third student id: ");

s3.studentId = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter third student name: ");

s3.studentName = System.Console.ReadLine();

System.Console.Write("Enter third student marks: ");

s3.marks = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.WriteLine();
//get data from first object

System.Console.WriteLine("Student ID: " + s1.studentId);

System.Console.WriteLine("Student Name: " + s1.studentName);

System.Console.WriteLine("Marks: " + s1.marks);

System.Console.WriteLine("----------------------------------");
 //get data from second object

System.Console.WriteLine("Student ID: " + s2.studentId);

System.Console.WriteLine("Student Name: " + s2.studentName);

System.Console.WriteLine("Marks: " + s2.marks);

System.Console.WriteLine("---------------------------------");

//get data from third object

System.Console.WriteLine("Student ID: " + s3.studentId);

System.Console.WriteLine("Student Name: " + s3.studentName);

System.Console.WriteLine("Marks: " + s3.marks);

System.Console.WriteLine("---------------------------------");

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods � Example 1 - Age

C:\Users\Harsha\AppData\Local\Microsoft\Windows\INetCacheContent.Word\Person.png
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodsExample�.
� Click on OK.

Program.cs

class Person

public int age = 20;

//method definition

public void Birthday()

age++;

class Program

static void Main()

Person p;

p = new Person();

System.Console.WriteLine(p.age);

p.Birthday(); //method calling

System.Console.WriteLine(p.age);
 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods � Example 2 - Numbers

C:\Users\Harsha\AppData\Local\Microsoft\Windows\INetCacheContent.Word\class
Class1.png
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodsExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodsExample2�. Click on OK.

Program.cs

//creating a class called "Class1"

class Class1

//"a" and "b" are used to store two numbers

public double a, b;

//"sum" is used to store the result of a+b

public double sum;

//"difference" is used to store the result of a-b

public double difference;

//"product" is used to store the result of a*b

public double product;

//"quotient" is used to store the result of a/b

public double quotient;

//Add method: stores the result of a + b into "sum"

public void Add()

{
sum = a + b;
 }

//Subtract method: stores the result of a - b into "difference"

public void Subtract()

difference = a - b;

//Multiply method: stores the result of a * b into "product"

public void Multiply()

product = a * b;

//Divide method: stores the result of a / b into "quotient"

public void Divide()

quotient = a / b;

class Program

static void Main()

//create reference variable of "Class1" class

Class1 c1;

//create object of "Class1" class

c1 = new Class1();

//read "a" from keyboard

System.Console.Write("Enter first number : ");

c1.a = System.Convert.ToDouble(System.Console.ReadLine());
 //read "b" from keyboard

System.Console.Write("Enter second number : ");

c1.b = System.Convert.ToDouble(System.Console.ReadLine());

//call Add method (it calculates a+b and stores the result in a data
member called "sum")

c1.Add();

//display the value of "sum"

System.Console.WriteLine("Sum: " + c1.sum);

//call Subtract method (it calculates a-b and stores the result in a data
member called "difference")

c1.Subtract();

//display the value of "difference"

System.Console.WriteLine("Difference: " + c1.difference);

//call Multiply method (it calculates a*b and stores the result in a data
member called "product")

c1.Multiply();

//display the value of "product"

System.Console.WriteLine("Product: " + c1.product);

//call Divide method (it calculates a/b and stores the result in a data
member called "quotient")

c1.Divide();

//display the value of "quotient"

System.Console.WriteLine("Quotient: " + c1.quotient);

 System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods � Example 3 - Login

C:\Users\Harsha\Dropbox\C#.NET\63. Login\class User.png

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LoginExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LoginExample�. Click on OK.

Program.cs

//create a class called "User"

class User

//"Username" is a data member to store username.

public string Username;

//"Password" is a data member to store password.

public string Password;

//"Message" is a data member to store message like "Successful login" or

"Invalid login".

public string Message;

//CheckLogin is a method that checks whether the username="admin"

and password="manager". If the conditions are matched, then it stores
"Successful login" in a data member called "Message"; otherwise it stores
"Invalid login".

public void CheckLogin()

if (Username == "admin" && Password == "manager")

{
 Message = "Successful login";

else

Message = "Invalid login";

class Program

static void Main()

//create reference variable of User class

User u;

//create object of User class

u = new User();

//read username from keyboard

System.Console.Write("Enter username : ");

u.Username = System.Console.ReadLine();

//read password from keyboard

System.Console.Write("Enter password : ");

u.Password = System.Console.ReadLine();

//call method called CheckLogin. It checks the username and password

and stores the result in a data member called "u.Message".
u.CheckLogin();

//show message

System.Console.WriteLine(u.Message);
 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods � Example 4 - Student

C:\Users\Harsha\AppData\Local\Microsoft\Windows\INetCacheContent.Word\Student -
Class and Objects.png
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StudentExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StudentExample�. Click on OK.

Program.cs

//create a class called "Student"

class Student

//data members

public int studentid;

public string studentname;

public double marks1, marks2, marks3, totalmarks, averagemarks;

public string grade;

//method "calculatetotalmarks" (calculates totalmarks)

public void calculatetotalmarks()

totalmarks = marks1 + marks2 + marks3;

//method "calculateaveragemarks" (calculates averagemarks)

public void calculateaveragemarks()

averagemarks = totalmarks / 3;

}
//method "calculategrade" (calculates grade)
 public void calculategrade()

if (marks1 < 35 || marks2 < 35 || marks3 < 35)

grade = "Fail";

else if (averagemarks >= 80 && averagemarks <= 100)

grade = "A grade";

else if (averagemarks >= 60 && averagemarks < 79)

grade = "B grade";

else if (averagemarks >= 50 && averagemarks < 59)

grade = "C grade";

else if (averagemarks >= 35 && averagemarks < 49)

grade = "D grade";

class Program

static void Main()

//create 2 reference variables of "Student" type

Student s1, s2;

//create 2 objects of "Student" type

s1 = new Student();

s2 = new Student();
//set data into first object

System.Console.Write("Enter first student id: ");

s1.studentid = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter first student name: ");

s1.studentname = System.Console.ReadLine();

System.Console.Write("Enter first student marks 1: ");

s1.marks1 = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter first student marks 2: ");

s1.marks2 = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter first student marks 3: ");

s1.marks3 = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.WriteLine();

//set data into second object

System.Console.Write("Enter second student id: ");

s2.studentid = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter second student name: ");

s2.studentname = System.Console.ReadLine();

System.Console.Write("Enter second student marks 1: ");

s2.marks1 = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter second student marks 2: ");

s2.marks2 = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.Write("Enter second student marks 3: ");

s2.marks3 = System.Convert.ToInt32(System.Console.ReadLine());

System.Console.WriteLine();

//call methods of first object

s1.calculatetotalmarks();

s1.calculateaveragemarks();
s1.calculategrade();

//call methods of second object

s2.calculatetotalmarks();

s2.calculateaveragemarks();

s2.calculategrade();
 //get data from first object

System.Console.WriteLine("First Student ID: " + s1.studentid);

System.Console.WriteLine("First Student Name: " + s1.studentname);

System.Console.WriteLine("First Student Marks 1: " + s1.marks1);

System.Console.WriteLine("First Student Marks 2: " + s1.marks2);

System.Console.WriteLine("First Student Marks 3: " + s1.marks3);

System.Console.WriteLine("First Student Total Marks: " +

s1.totalmarks);

System.Console.WriteLine("First Student Average Marks: " +

s1.averagemarks);

System.Console.WriteLine("First Student Grade: " + s1.grade);

System.Console.WriteLine("---------------------------------");

//get data from second object

System.Console.WriteLine("Second Student ID: " + s2.studentid);

System.Console.WriteLine("Second Student Name: " +

s2.studentname);

System.Console.WriteLine("Second Student Marks 1: " + s2.marks1);

System.Console.WriteLine("Second Student Marks 2: " + s2.marks2);

System.Console.WriteLine("Second Student Marks 3: " + s2.marks3);

System.Console.WriteLine("Second Student Total Marks: " +

s2.totalmarks);

System.Console.WriteLine("Second Student Average Marks: " +

s2.averagemarks);

System.Console.WriteLine("Second Student Grade: " + s2.grade);

System.Console.WriteLine("---------------------------------");

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Constructors in C#.NET

Constructors

� Constructors are special methods of the class, which initializes the data
members and perform any initialization process, which will be called
automatically when an object is created for the class.
� Constructors are used to receive a set of parameters and initialize those
parameters into respective data members.
� For example, you have a class with data members. So your constructor can
receive 3 arguments and assign those arguments into data members
respectively. However, if you don�t want to initialize all the data members,
you can receive less no. of arguments also. For example, you can initialize 1
or 2 data members also.
� When an object is created, the following process happens internally:
o Memory will be allocated for the object in RAM (in Heap of RAM).
o Default values will be initialized (based on the data type).
o Constructor will be called automatically.
Syntax of Constructor

public Classname(datatype variable1, datatype variable2, �)

Datamember1 = variable1;

Datamember2 = variable2;

Types of Constructor

� Parameter-less constructor: A constructor that has no arguments. It

initializes data members with some fixed values.
� Parameterized constructor: A constructor that has one or more
arguments. It initializes data members with argument (varied) values.

Default Constructor

� As per the rules of c#.net, a class should have a constructor. If you don�t
create a constructor in the class, .net creates an empty constructor (implicit
constructor or default constructor) automatically and internally.
Parameterless Constructor - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ParameterlessConstructorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ParameterlessConstructorExample�.
� Click on OK.

Program.cs

class Sample

//data members

public int a, b;

//constructor

public Sample()

a = 10;

b = 20;

class Program

static void Main()

//creating reference variable

 Sample s;

//creating object

s = new Sample();

//get data

System.Console.WriteLine(s.a);

System.Console.WriteLine(s.b);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Parameterized Constructor - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ParameterizedConstructorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ParameterizedConstructorExample�.
� Click on OK.

Program.cs

class Sample

//data members

public int a, b;

//constructor

public Sample(int x, int y)

a = x;

b = y;

class Program

static void Main()

//creating reference variable

 Sample s1, s2;

//creating objects

s1 = new Sample(10, 20);

s2 = new Sample(60, 70);

//get data

System.Console.WriteLine("s1.a is " + s1.a);

System.Console.WriteLine("s1.b is " + s1.b);

System.Console.WriteLine("s2.a is " + s2.a);

System.Console.WriteLine("s2.b is " + s2.b);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Constructors - Student - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConstructorsStudentExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConstructorsStudentExample�.
� Click on OK.

Program.cs

//create a class called "Student" with 3 data members called "studentid",

"studentname" and "marks"

class Student

//data members

public int studentid;

public string studentname;

public int marks;

//constructor (to receive parameters & initialize them into respetive data
members)

public Student(int a, string b, int c)

studentid = a;

studentname = b;

marks = c;

}
class Program

static void Main()

//create 3 reference variables of "Student" type

Student s1, s2, s3;

//create 3 objects of "Student" type

s1 = new Student(101, "Scott", 70);

s2 = new Student(102, "Allen", 80);

s3 = new Student(103, "John", 90);

//get data from first object

System.Console.WriteLine("First student:");

System.Console.WriteLine("Student ID: " + s1.studentid);

System.Console.WriteLine("Student Name: " + s1.studentname);

System.Console.WriteLine("Marks: " + s1.marks);

System.Console.WriteLine("----------------------------------");

//get data from second object

System.Console.WriteLine("Second student:");

System.Console.WriteLine("Student ID: " + s2.studentid);

System.Console.WriteLine("Student Name: " + s2.studentname);

System.Console.WriteLine("Marks: " + s2.marks);

System.Console.WriteLine("---------------------------------");

//get data from third object

System.Console.WriteLine("Third student:");

System.Console.WriteLine("Student ID: " + s3.studentid);

System.Console.WriteLine("Student Name: " + s3.studentname);

System.Console.WriteLine("Marks: " + s3.marks);

System.Console.WriteLine("---------------------------------");
 System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Object Initializer in C#.NET

Object Initializer

� Drawback of constructor: Once we have created a constructor with some

set of arguments, every time we call it, you must pass the same no. of
values; we can't initialize desired data members; so there is no flexibility in
the constructor.
� Object initializer solves the above problem.
� �Object initializer� is a syntax, which is used to initialize �desired� data
members.
� "Object initializer" concept introduced in c#.net 3.0.
� "Object initializer" will be called after constructor.

� Syntax of creating object based on a class using Object

Initializer:

{ DataMember1 = Value1, DataMember2 = Value2, � };

� When an object is created, the following process happens

internally:
o First, necessary memory will be allocated for the object in RAM.
o Default values will be initialized into the data members.
o Next, constructor will be called automatically.
o Next, object initializer will be called automatically.
Object Initializer - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ObjectInitializerExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ObjectInitializerExample�.
� Click on OK.

Program.cs

//create a class called "Student" with 3 data members called "studentid",

"studentname" and "marks"

class Student

//data members

public int studentid;

public string studentname;

public int marks;

class Program

static void Main()

//create 3 reference variables of "Student" type

Student s1, s2, s3;

//create 3 objects of "Student" type

s1 = new Student() { studentid = 101, studentname = "Scott", marks = 70 };

 s2 = new Student() { studentid = 102, studentname = "Allen", marks = 80 };

s3 = new Student() { studentid = 103, studentname = "John", marks = 90 };

//get data from first object

System.Console.WriteLine("First student:");

System.Console.WriteLine("Student ID: " + s1.studentid);

System.Console.WriteLine("Student Name: " + s1.studentname);

System.Console.WriteLine("Marks: " + s1.marks);

System.Console.WriteLine("----------------------------------");

//get data from second object

System.Console.WriteLine("Second student:");

System.Console.WriteLine("Student ID: " + s2.studentid);

System.Console.WriteLine("Student Name: " + s2.studentname);

System.Console.WriteLine("Marks: " + s2.marks);

System.Console.WriteLine("----------------------------------");

//get data from third object

System.Console.WriteLine("Third student:");

System.Console.WriteLine("Student ID: " + s3.studentid);

System.Console.WriteLine("Student Name: " + s3.studentname);

System.Console.WriteLine("Marks: " + s3.marks);

System.Console.WriteLine("----------------------------------");

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"this" keyword in C#.NET

this keyword

� �this� is a keyword, which represents �current object�, based on which, the

method or constructor was called.
� �this� keyword can be used in non-static methods and non-static
constructors only. �this� keyword can�t be used in static methods or static
constructors.
� It is used to access the members of current object.
� By default, the usage of �this� keyword is optional. By default system
referrers to �current object�. But when a local variable name and data
member name are same, then by default the system refers to local variable.
Then if you want to access data member name, you must use
�this.datamember�. So in that way �this� keyword is must to use.

C:\Users\Harsha\Dropbox\C#.NET\65. This\this.png
"this" keyword - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ThisExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ThisExample�. Click on OK.

Program.cs

//create a class called "Class1"

class Class1

//"n" is a data member that stores a number

public int n;

//"Display" method

public void Display()

//"n" is a local variable

int n = 50;

//Note: Here the local variable "n" and data member "n" having same
name. In this situation, by default "n" refers to "local variable" and "this.n"
refers to "data member".

//this = current object

//this.n = data member

System.Console.WriteLine("data member: " + this.n);

System.Console.WriteLine("local variable: " + n);

System.Console.WriteLine();
 }

class Program

static void Main()

//create two reference variables of "Class1" type

Class1 c1, c2;

//create first object

c1 = new Class1();

//create second object

c2 = new Class1();

//set value into c1.n and c2.n

c1.n = 100;

c2.n = 200;

c1.Display(); //"this" means first object

c2.Display(); //"this" means second object

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"Set" and "Get" Methods in C#.NET

Set Method and Get Method

� �Set methods� and �get methods� are used to perform �validation� on a

private data member.
� You must create the data member as �private data member�, for security.

Set Method

� Set method receives a value as argument, checks (validates) it, and then
assigns the same into the data member.
� Set method protects the data member from invalid values.
� Set method acts as mediator between Main method and data member.
� Set method is used to perform validations and makes the program stronger
and systematic.
� Note: When set method is created, it is recommended to make the data
member as �private�. The private members are accessible only within the
same class.

� Syntax of Set Method:

public void SetDatamembername(Datatype Argument)

Datamember = Argument;

}
Get Method

� Get method returns the value of a data member.

� Get method can perform automatic calculations.
� Syntax of Get Method:

public Returntype GetDatamembername( )

return (Datamember);

}
"Set" and "Get" Methods - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SetAndGetMethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SetAndGetMethodsExample�.
� Click on OK.

Program.cs

//create a class called "Person"

class Person

//data member

public int age;

//set method

public void SetAge(int value)

if (value >= 18 && value <= 60)

age = value;

//get method

public int GetAge()

{
 return (age);

class Program

static void Main()

Person p = new Person();

p.SetAge(70);

System.Console.WriteLine(p.GetAge());

p.SetAge(24);

System.Console.WriteLine(p.GetAge());

p.SetAge(240);

System.Console.WriteLine(p.GetAge());

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Properties in C#.NET

Properties

� A property is a group of �set method� and �get method�, which perform

validation on a private data member.
� Properties are used to implement a protection layer around data member.
� Properties can't store any value.
� Properties are used for validations and automatic calculations. The �set
method� is used to create validations; and �get method� is used to create
automatic calculations or return the value of a data member as it is.
� Properties offer simple way to call �set method� and �get method�.
� In real time, for every private data member, we create a property. That
means the private data member is not accessible directly in the client code;
though property it can be accessible indirectly.
� The property�s set method will be called automatically when a value is
assigned to a property.
� The property�s set method has an implicit argument called �value� that
represents the value assigned to the property.
� The property�s get method will be called automatically when the client code
gets the value of the property.
� The property�s get method has no arguments but should return the value.
� Note: While creating properties, it is recommended to create data member
name start with �_� (underscore). The underscore has no meaning, but it
indicates that it is data member.
Syntax to create a property:

public Datatype Propertyname

set

Datamember = value;

get

return (Datamember);

}
Properties - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �PropertiesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �PropertiesExample�.
� Click on OK.

Program.cs

//create a class called "Person"

class Person

//private data member

private int _age;

//property (set + get)

public int Age

set

if (value >= 18 && value <= 60)

_age = value;

get

{
 return _age;

class Program

static void Main()

Person p = new Person();

p.Age = 70;

System.Console.WriteLine(p.Age);

p.Age = 24;

System.Console.WriteLine(p.Age);

p.Age = 240;

System.Console.WriteLine(p.Age);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Readonly and WriteOnly Properties in
C#.NET

Read-only properties

� Read-only properties contain only get method; no set method.

� The user can get the value of read-only property, but can�t set the value.

� Syntax to create a readonly property:

public Datatype Propertyname

get

return (Datamember);

Write-only properties

� Write-only properties contain only set method; no get method.

� The user can set the value of write-only property, but can�t get
the value.

� Syntax to create a write-only property:

public Datatype Propertyname

set

Datamember = value;

}
Readonly Properties - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ReadOnlyPropertiesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ReadOnlyPropertiesExample�.
� Click on OK.

Program.cs

class Student

//private data members

public int _marks;

public string _result;

//properties

public int Marks

set

if (value >= 0 && value <= 100)

_marks = value;

get

return (_marks);

}
 }

//readonly property (only get method)

public string Result

get

if (_marks < 35)

_result = "Fail";

else

_result = "Pass";

return _result;

class Program

static void Main()

Student s = new Student();

s.Marks = 70;

System.Console.WriteLine(s.Result);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Automatic Properties in C#.NET

Automatic properties

� Automatic properties are created using { get; set; } syntax.

� When you create automatic property, the compiler automatically creates
the following things automatically at compilation time:
o Private data member
o Set method
o Get method

� Advantage of automatic properties: Easy syntax to create simple

properties.
� But automatic properties are useful only when you don�t want to perform
any validation. If you want to perform validation, use normal properties.
� Syntax:

public Datatype Propertyname { get; set; }

Automatic Properties - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.5�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AutomaticPropertiesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AutomaticPropertiesExample�.
� Click on OK.

Program.cs

class Person

//automatic properties

public string PersonName { get; set; }

public int Age { get; set; }

class Program

static void Main()

Person p = new Person();

p.PersonName = "Scott";

p.Age = 22;

System.Console.WriteLine(p.PersonName);

System.Console.WriteLine(p.Age);

System.Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Objects as Arguments in C#.NET

Objects as Arguments

� We can pass objects as arguments from one method to another method.

Then the reference (address) of the source object will be sent to the
argument variable.
Objects as Arguments - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ObjectsAsArgumentsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ObjectsAsArgumentsExample�.
� Click on OK.

Program.cs

class Person

public int age;

class Sample

public void Birthday(Person p)

p.age++;

class Program

static void Main()

Person p;

p = new Person();
 Sample s;

s = new Sample();

p.age = 20;

s.Birthday(p);

System.Console.WriteLine(p.age);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Multiple Objects as Arguments in C#.NET

Multiple Objects as Arguments

� We can pass multiple objects as arguments from one method to another

method. Then the references of the source objects will be sent to the
respective argument variables.
Multiple Objects as Arguments - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MultipleObjectsAsArgumentsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultipleObjectsAsArgumentsExample�.
� Click on OK.

Program.cs

//class

class Student

public int studentid;

public string studentname;

public int marks;

//create a class called "Class1"

class Class1

//create a method called "mymethod" in "Class1" that receives two

objects of "Student" class into "studentvariable1" and "studentvariable2"
arguments respectively

public void mymethod(Student studentvariable1, Student

studentvariable2)

//display the details of studentvariable1

 System.Console.WriteLine("First Student details are: ");

System.Console.WriteLine("Student ID: " + studentvariable1.studentid);

System.Console.WriteLine("Student Name: " +

studentvariable1.studentname);

System.Console.WriteLine("Marks: " + studentvariable1.marks);

System.Console.WriteLine();

//display the details of studentvariable2

System.Console.WriteLine("Second Student details are: ");

System.Console.WriteLine("Student ID: " + studentvariable2.studentid);

System.Console.WriteLine("Student Name: " +

studentvariable2.studentname);

System.Console.WriteLine("Marks: " + studentvariable2.marks);

class Program

static void Main()

//create two reference variables of Student type

Student s1, s2;

//create two objects of Student type

s1 = new Student();

s2 = new Student();

//set data into the members of "studentvariable1"

s1.studentid = 1;

s1.studentname = "scott";
s1.marks = 80;

//set data into the members of "studentvariable2"

s2.studentid = 2;

s2.studentname = "allen";
 s2.marks = 70;

//create a reference variable of Class1 type

Class1 c1;

//create an object of Class1 type

c1 = new Class1();

//call mymethod of Class1 and pass studentvariable1 and

studentvariable2. That method receives both objects and display them.

c1.mymethod(s1, s2);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Objects as Data Members in C#.NET

Objects as Data Members

� We can create an object of one class (source class) and store its reference in
a data member of another class (destination class).
� If you do so, we can access the source class�s object, through the data
member of destination class. Then the data type of the data member should
be �source class� type.
� For example, assume you have a class called �Hyderabad�. You can create an
object for �Hyderabad� class and store its reference in a data member called
�h� in another class called �India�.
Objects as Data Members - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ObjectsAsDataMembersExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ObjectsAsDataMembersExample�.
� Click on OK.

Program.cs

//create a class called "Hyderabad" with 2 data members called

"Charminar" and "Golconda"

class Hyderabad

public string Charminar = "Hyderabad.Charminar";

public string Golconda = "Hyderabad.Golconda";

//create a class called "India"

class India

//create an object of "Hyderabad" and store its reference in a data

member of "India" class

public Hyderabad h = new Hyderabad();

class Program

{
 static void Main()

//create a reference variable of India type

India i;

//create an object of India type

i = new India();

//get the members of "Hyderabad" class, through "India" class

System.Console.WriteLine(i.h.Charminar);

System.Console.WriteLine(i.h.Golconda);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Inheritance in C#.NET

What is Inheritance

� It is a OOP concept of creating �parent-child� relationship among

two or more classes.
� It is a concept of extending an existing class, by creating another
class based on the existing class.
� Here, the classes are two types: parent class and child class.
� Child class extends the parent class.
� Parent class also called as �base class� or �super class�.
� Child class also called as �derived class� or �sub class�.
� As a result of inheritance, all the members of parent class will
become as members of child class automatically.
� When an object of child class is created, it creates an object of
parent class internally, and it will be part of the child class�s
object.
� One parent class can have one or more child classes; but one
child class can have ONLY ONE parent class.
� If you create a new child class based on an existing child class, all
its members and also its parent class members will be inherited
into the new child class.
� Syntax of inheritance:

class Childclassname : Parentclassname

}
Inheritance - Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InheritanceExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InheritanceExample�.
� Click on OK.

Program.cs

//parent class

class Class1

public int a = 10;

public int b = 20;

//child class

class Class2 : Class1

public int c = 30;

public int d = 40;

class Program

static void Main()

//create a reference variable for child class (Class2)

Class2 p;
 //create object for child class (Class2); It internally creates an object for
parent class also. That means it allocates memory for "a", "b", "c" and "d".

p = new Class2();

//child class data members

System.Console.WriteLine("c: " + p.c);

System.Console.WriteLine("d: " + p.d);

//parent class data members

System.Console.WriteLine("a: " + p.a);

System.Console.WriteLine("b: " + p.b);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Inheritance � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InheritanceExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InheritanceExample2�.
� Click on OK.

Program.cs

//parent class

class Person

public string PersonName;

public string Gender;

//child class 1

class Student : Person

public int StudentID;

public int Marks;

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

}

class Program

static void Main()

/******* creating object for parent class ********/

Person p;

p = new Person();

p.PersonName = "Scott";

p.Gender = "Male";

System.Console.WriteLine("Person Name: " + p.PersonName);

System.Console.WriteLine("Gender: " + p.Gender);

System.Console.WriteLine("\n");

/******** creating object for child class 1 ********/

Student s;

s = new Student();

s.PersonName = "Allen";

s.Gender = "Male";

s.StudentID = 101;

s.Marks = 70;

System.Console.WriteLine("Student Name: " + s.PersonName);

System.Console.WriteLine("Gender: " + s.Gender);

System.Console.WriteLine("Student ID: " + s.StudentID);

System.Console.WriteLine("Student Marks: " + s.Marks);

System.Console.WriteLine("\n");

/******** creating object for child class 2 *********/

Employee emp;

emp = new Employee();

emp.PersonName = "Jones";

emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;
 System.Console.WriteLine("Employee Name: " + emp.PersonName);

System.Console.WriteLine("Gender: " + emp.Gender);

System.Console.WriteLine("Employee ID: " + emp.EmpID);

System.Console.WriteLine("Employee Salary: " + emp.Salary);

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�base� keyword in C#.NET

Calling the parent class�s member from child class�s

method:

� To access the members of parent class within the child class�s method:
o Syntax: base.parentclassmembername

� Note: Here, �base� is a keyword that represents the �object of parent class�,
which is a part of �object of child class�.
�base� keyword - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �BaseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �BaseExample�.
� Click on OK.

Program.cs

//parent class

class Person

public string PersonName;

public string Gender;

//child class 1

class Student : Person

public int StudentID;

public int Marks;

//Student.DisplayStudentDetails

public void DisplayStudentDetails()

System.Console.WriteLine("Student Name: " + base.PersonName);

System.Console.WriteLine("Gender: " + base.Gender);

System.Console.WriteLine("Student ID: " + this.StudentID);

System.Console.WriteLine("Student Marks: " + this.Marks);

 }

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

//Employee.DisplayEmployeeDetails

public void DisplayEmployeeDetails()

System.Console.WriteLine("Employee Name: " + base.PersonName);

System.Console.WriteLine("Gender: " + base.Gender);

System.Console.WriteLine("Employee ID: " + this.EmpID);

System.Console.WriteLine("Employee Salary: " + this.Salary);

class Program

static void Main()

/********* creating object for child class 1 *************/

Student s;

s = new Student();

s.PersonName = "Allen";

s.Gender = "Male";

s.StudentID = 101;
s.Marks = 70;

s.DisplayStudentDetails();

System.Console.WriteLine("\n");

/********* creating object for child class 2 *************/

Employee emp;
 emp = new Employee();

emp.PersonName = "Jones";

emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;

emp.DisplayEmployeeDetails();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Parent class�s constructor in C#.NET

Calling the parent class�s constructor from child class�s

constructor:

� The parent class�s parameterless constructor will be called automatically,

when child class�s constructor was called. But you must call the parent
class�s parameterized constructor explicitly in the child class�s constructor.
� In the child class�s constructor, you can use the following syntax to call the
parent class�s parameterized constructor:
o base(parameter1, parameter2, �)
Parent class�s constructor - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ParentClassConstructorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ParentClassConstructorExample�.
� Click on OK.

Program.cs

//parent class

class Person

public string PersonName;

public string Gender;

//parent class constructor

public Person(string PersonName, string Gender)

this.PersonName = PersonName;

this.Gender = Gender;

//child class 1

class Student : Person

public int StudentID;

 public int Marks;

//child class's constructor

//We are receiving 4 values; First two values will be forwarded to the
parent class constructor; Remaining two values will be stored in the child
class's object.

public Student(string PersonName, string Gender, int StudentID, int

Marks) : base(PersonName, Gender)

this.StudentID = StudentID;

this.Marks = Marks;

//Student.DisplayStudentDetails

public void DisplayStudentDetails()

System.Console.WriteLine("Student Name: " + base.PersonName);

System.Console.WriteLine("Gender: " + base.Gender);

System.Console.WriteLine("Student ID: " + this.StudentID);

System.Console.WriteLine("Student Marks: " + this.Marks);

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

//child class's constructor

//We are receiving 4 values; First two values will be forwarded to the
parent class constructor; Remaining two values will be stored in the child
class's object.

public Employee(string PersonName, string Gender, int EmpID, int

Salary) : base(PersonName, Gender)
 {

this.EmpID = EmpID;

this.Salary = Salary;

//Employee.DisplayEmployeeDetails

public void DisplayEmployeeDetails()

System.Console.WriteLine("Employee Name: " + base.PersonName);

System.Console.WriteLine("Gender: " + base.Gender);

System.Console.WriteLine("Employee ID: " + this.EmpID);

System.Console.WriteLine("Employee Salary: " + this.Salary);

class Program

static void Main()

/********* creating object for child class 1 *************/

Student s;

s = new Student("Allen", "Male", 101, 70);

s.DisplayStudentDetails();

System.Console.WriteLine("\n");

/********* creating object for child class 2 *************/

Employee emp;

emp = new Employee("Jones", "Male", 201, 7000);

 emp.DisplayEmployeeDetails();

System.Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Method Hiding in C#.NET

Method Hiding

� �Method hiding� is used to hide the parent class�s method, by creating

another method in the child class, with same signature (access modifier,
method name and arguments).
� For method hiding, we need not use any special keyword in the parent
class�s method. But we have to use �new� keyword in the child class�s
method optionally. The �new� keyword specifies the compiler that we are
doing the �method hiding� intentionally.

Syntax to create normal method (in parent class):

public Returntype Methodname(Datatype1 Argument1, DataType2

Argument2, �)

Code here

Syntax to create hiding method (in child class):

public new Returntype Methodname (Datatype1 Argument1,

DataType2 Argument2, �)

Code here

}
Method Hiding - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodHidingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodHidingExample�.
� Click on OK.

Program.cs

//parent class

class Class1

//Class1.Display

public void Display()

System.Console.WriteLine("Class1.Display");

//child class

class Class2 : Class1

//Class2.Display

//Method hiding: This method hides the parent class's method called
"Display". Both methods are having the same signature; but code is
different. Note: The "new" keyword is optional here.

public new void Display()

{
 System.Console.WriteLine("Class2.Display");

class Program

static void Main()

Class2 c2;

c2 = new Class2();

c2.Display(); //calls Class2.Display only

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Method Hiding � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodHidingExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodHidingExample2�.
� Click on OK.

Program.cs

//parent class

class Person

//data members of "Person" class

public string PersonName;

public string Gender;

//Person.Display

public void Display()

System.Console.WriteLine("Person Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

//child class 1

class Student : Person

public int StudentID;

public int Marks;

 //Student.Display

//Method Hiding: This method hides the parent class's method called
"Display". Both methods are having the same signature; but code is
different.

public new void Display()

System.Console.WriteLine("Student Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

System.Console.WriteLine("Student ID: " + StudentID);

System.Console.WriteLine("Student Marks: " + Marks);

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

//Employee.Display

//Method Hiding: This method hides the parent class's method called
"Display". Both methods are having the same signature; but code is
different.

public new void Display()

System.Console.WriteLine("Employee Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

System.Console.WriteLine("Employee ID: " + EmpID);

System.Console.WriteLine("Employee Salary: " + Salary);

class Program
{

static void Main()

/********* creating object for child class 1 *************/

 Student s;

s = new Student();

s.PersonName = "Allen";

s.Gender = "Male";

s.StudentID = 101;

s.Marks = 70;

s.Display(); //calls Student.Display only

System.Console.WriteLine();

/********* creating object for child class 2 *************/

Employee emp;

emp = new Employee();

emp.PersonName = "Jones";

emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;

emp.Display(); //calls Employee.Display only

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Method Overriding in C#.NET

Virtual Methods and Method Overriding

� �Method Overriding� is a concept of �extending a parent class�s method�, by

creating another method in the child class, with same name and same
signature.
� The parent class�s method should be �virtual method�. The child class�s
method should be �override method�.
� The �virtual� keyword in parent class�s method allows the child classes to
override (redefine) the parent class�s method in the child classes.
� The �override� keyword in child class�s method informs the parent class that
it is overriding the parent class�s virtual method.
� The virtual methods only can be overridden.
� The method signature (method name, access modifier, arguments, and
return type) should be same in between virtual method and override
method.
� Virtual methods can�t be private.
� Overriding the virtual methods is optional.
� In real time, we use �method overriding� to extend an existing method,
which is created by another programmer.

Normal Methods (vs) Virtual Methods

Sl. No

Normal Method

Virtual Method

No "virtual" keyword

Should have "virtual" keyword.

Present in any class (parent class

or in child class).

Should be present in parent class

only.
Method Hiding (vs) Method Overrinding

� "Method Hiding" is similar to "Method Overriding", but having the following

differences.

Sl.
No

Method Hiding

Method Overriding

We need not use any keyword in

parent class method; "new" keyword
in child class method.

We should use "virtual" keyword in

parent class method; "override"
keyword in child class method.

Method hiding is used to hide

(overwrite) the parent class�s method.
That means parent class�s method will
not execute; only child class�s method
executes.

Method overriding is used to extend

the parent class�s method. That
means both parent class�s method
and child class�s method execute.

Syntax to create virtual method (in parent class):

public virtual Returntype Methodname (Datatype1 Argument1,

DataType2 Argument2, �)

Code here

Syntax to create override method (in child class):

public override Returntype Methodname (Datatype1 Argument1,

DataType2 Argument2, �)
{

Code here

}
Method Overriding - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodOverridingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodOverridingExample�.
� Click on OK.

Program.cs

//parent class

class Class1

//Class1.Display (virtual method)

public virtual void Display()

System.Console.WriteLine("Class1.Display");

//child class

class Class2 : Class1

//Class2.Display

//Method overriding: This method overrides (extends) the parent class's

virtual method called "Display". That means both methods will execute.
Both methods should have same signature.

public override void Display()

{
 base.Display();

System.Console.WriteLine("Class2.Display");

class Program

static void Main()

Class2 myobject;

myobject = new Class2();

//call the both methods Class1.Display and Class2.Display

myobject.Display();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Method Overriding � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MethodOverridingExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MethodOverridingExample2�.
� Click on OK.

Program.cs

//parent class

class Person

public string PersonName;

public string Gender;

//Person.Display (virtual method)

public virtual void Display()

System.Console.WriteLine("Person Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

//child class 1

class Student : Person

public int StudentID;

public int Marks;

 //Student.Display

//Method overriding: This method overrides (extends) the parent class's

virtual method called "Display". Both methods will execute. Both methods
should have same signature.

public override void Display()

base.Display();

System.Console.WriteLine("Student ID: " + StudentID);

System.Console.WriteLine("Student Marks: " + Marks);

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

//Employee.Display

//Method overriding: This method overrides (extends) the parent class's

virtual method called "Display". Both methods will execute. Both methods
should have same signature.

public override void Display()

base.Display();

System.Console.WriteLine("Employee ID: " + EmpID);

System.Console.WriteLine("Employee Salary: " + Salary);

class Program

static void Main()

{
/********* creating object for child class 1 *************/

Student s;

s = new Student();

s.PersonName = "Allen";
 s.Gender = "Male";

s.StudentID = 101;

s.Marks = 70;

s.Display(); //calls to Person.Display and Employee.Display

System.Console.WriteLine("\n");

/********* creating object for child class 2 *************/

Employee emp;

emp = new Employee();

emp.PersonName = "Jones";

emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;

emp.Display(); //calls to Person.Display and Student.Display

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Abstract Classes in C#.NET

Abstract Classes

� Abstract classes are similar to normal classes and can contain abstract
members additionally, and those can�t be instantiated.
� Abstract classes are created using �abstract� keyword
� Abstract classes contain a set of members that are common to all of its child
classes.
� Abstract classes can be inherited. That means we can create a child class
based on the abstract class.
� We can�t create object for the abstract class directly. The only way to utilize
its members is �creating object for child class and calling abstract class�s
members through the child class�s object�.
� Syntax to create an abstract class:

abstract class Classname

Normal Class (vs) Abstract Class

Sl.
No

Normal Class

(or) Non-abstract class

Abstract class

No "abstract" keyword

Should have "abstract" keyword.

We can create an object for normal

class.

We can't create an object for abstract

class; but we can create a reference
variable.

Normal class can't contain abstract

methods.

Abstract class can contain abstract

methods.
Abstract Classes - Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AbstractClassesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AbstractClassesExample�. Click on OK.

Program.cs

//parent class (abstract class)

abstract class Person

//normal method in abstract class

public void Display()

System.Console.WriteLine("Person.Display");

//child class 1

class Student : Person

//child class 2

class Employee : Person

class Program
{
 static void Main()

/************* creating object for child class 1 *********/

Student s;

s = new Student();

s.Display();

System.Console.WriteLine("\n");

/************* creating object for child class 1 **********/

Employee emp;

emp = new Employee();

emp.Display();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Abstract Classes � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AbstractClassesExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AbstractClassesExample2�.
� Click on OK.

Program.cs

//parent class (abstract class)

abstract class Person

public string PersonName;

public string Gender;

//normal method in abstract class

public void Display()

System.Console.WriteLine("Person name: " + this.PersonName);

System.Console.WriteLine("Gender: " + this.Gender);

//child class 1

class Student : Person

public int StudentID;

public int Marks;

}

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

class Program

static void Main()

/************* creating object for child class 1 ********************/

Student s;

s = new Student();

s.PersonName = "Allen";

s.Gender = "Male";

s.StudentID = 101;

s.Marks = 70;

s.Display();

System.Console.WriteLine("Student ID: " + s.StudentID);

System.Console.WriteLine("Marks: " + s.Marks);

System.Console.WriteLine("\n");

/************* creating object for child class 2 ********************/

Employee emp;

emp = new Employee();

emp.PersonName = "Jones";
emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;

emp.Display();

System.Console.WriteLine("Employee ID: " + emp.EmpID);

System.Console.WriteLine("Salary: " + emp.Salary);

 System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Abstract Methods in C#.NET

Abstract Methods

� Abstract methods are �declaration-only� method that are declared in the

abstract class (parent class) and must be implemented (overridden) in the
child class(es).
� Abstract methods can be created only within the abstract class.
� Abstract methods contain only declaration (signature or prototype).
� Signature = Method name, return type, arguments and access modifier.
� Abstract methods should be overridden in the child class, using �override�
keyword.
� In real time, abstract class with abstract method(s) will be created by one
programmer and its child class(es) will be created by another programmer.
� Assume that there are two programmers. The first programmer is creating
parent class (cum abstract class); the second programmer is creating child
class. But both are present in two different components (parts) of the
project. So whenever the first programmer can�t write the actual code for a
method in the parent class and wants to let the second programmer two
write actual code for the method, then he will create an abstract method in
the parent class. So the first programmer writes method signature only; but
not the method definition. Then the second programmer has to create a
child class, based on the existing parent class. Then the second programmer
must create method definition. This work is called as �method overriding
with abstract methods�.
� Note: �Method overriding of virtual methods� is optional; but �method
overriding of abstract methods� is must.
� Virtual methods contain method body also. Abstract methods contain
signature only, no method body.
Normal Method (vs) Abstract Method

Sl.
No

Normal method

(or) Non-abstract method

Abstract method

No "abstract" keyword

Should have "abstract" keyword.

We can call the normal method.

We can't call the abstract method.

Normal methods can be created in

both normal class and also in
abstract class.

Abstract methods can be created in

only abstract class.

Normal methods contain method

signature and body.

Abstract methods contain only

method signature; no method body.

Normal methods can be present in

both parent class and also in the
child class.

Abstract methods can be present only

in the parent class.

Normal methods can be 'private'.

Abstract methods can't be 'private'.

Virtual Method (vs) Abstract Method

Sl.
No

Virtual method

Abstract method

Should have "virtual" keyword.

Should have "abstract" keyword.

We can call the virtual method.

We can't call the abstract method.

Virtual methods can be created in

both normal class and also in
abstract class.

Abstract methods can be created in

only abstract class.

Virtual methods contain method

signature and body.

Abstract methods contain only

method signature; no method body.

Overriding the virtual methods is

optional.

Overriding the abstract methods is

must.

� Syntax to create abstract method (in parent class):

public abstract Returntype Methodname(Datatype1

Argument1, DataType2 Argument2, �);
� Syntax to create override method (in child class):

public override Returntype Methodname(Datatype1

Argument1, DataType2 Argument2, �)

Code here

}
Abstract Methods - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AbstractMethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AbstractMethodsExample�.
� Click on OK.

Program.cs

//parent class (abstract class)

abstract class Class1

//abstract method in parent class. Abstract method doesn't contain

method body. It contains only signature.

public abstract void Display();

//child class

class Class2 : Class1

//Class2.Display

//Method overriding: This method overrides the parent class's abstract

method called "Display". Both methods are having the same signature.

public override void Display()

System.Console.WriteLine("Class2.Display");

}
}

class Program

static void Main()

Class2 c2;

c2 = new Class2();

c2.Display();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Abstract Methods � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AbstractMethodsExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AbstractMethodsExample2�.
� Click on OK.

Program.cs

//parent class (abstract class)

abstract class Person

public string PersonName;

public string Gender;

//abstract method in parent class. Abstract method doesn't contain

method body. It contains only method signature.

public abstract void Display();

//child class 1

class Student : Person

public int StudentID;

public int Marks;

//Student.Display
 //Method Overriding: This method overrides the parent class's abstract
method called "Display". Both methods are having the same signature.

public override void Display()

System.Console.WriteLine("Student Name: " + base.PersonName);

System.Console.WriteLine("Gender: " + base.Gender);

System.Console.WriteLine("Student ID: " + this.StudentID);

System.Console.WriteLine("Student Marks: " + this.Marks);

//child class 2

class Employee : Person

public int EmpID;

public double Salary;

//Employee.Display

//Method overriding: This method overrides the parent class's abstract

method called "Display". Both methods are having the same signature.

public override void Display()

System.Console.WriteLine("Employee Name: " + base.PersonName);

System.Console.WriteLine("Gender: " + base.Gender);

System.Console.WriteLine("Employee ID: " + this.EmpID);

System.Console.WriteLine("Employee Salary: " + this.Salary);

class Program
{

static void Main()

/*********** creating object for child class 1 *****************/

Student s;
 s = new Student();

s.PersonName = "Allen";

s.Gender = "Male";

s.StudentID = 101;

s.Marks = 70;

s.Display();

System.Console.WriteLine("\n");

/*********** creating object for child class 2 *****************/

Employee emp;

emp = new Employee();

emp.PersonName = "Jones";

emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;

emp.Display();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Interfaces in C#.NET

Interfaces

� Interfaces are similar to abstract classes, but interfaces contain only

abstract methods and property declarations.
� We can�t create other members such as data members, normal methods,
constructors, properties etc., in interface.
� It is recommended to start the name of the interface with �I�.
� We can�t create an object for the interface, but we can create one or more
child classes for interface.
� Interface provides a list of abstract methods that should be overridden in
the child classes. By default, all the interface methods �public� and
�abstract� automatically.
� All the child classes that inherits (implements) the interface should
implement (override) all the interface methods. But different child classes
can implement the interface methods with different code. If you don�t
implement (override) any of the interface methods in the child class, you will
get compile-time error.
� Real-time use of interface: Interface acts as �contract� or �bridge�
between two parts of a project. Assume that there are two programmers
that create two different components of the project. The interface acts as
bridge between both the programmers. This situation occurs in advanced
.net frameworks such as WPF, MVC etc.
o The first programmer creates an interface; then creates an interface
variable and calls the method, without knowing its implementation.
o The second programmer creates a child class for the interface and
implements all of its methods, without knowing its calling.
Abstract Class (vs) Interface

Sl.
No

Abstract Class

Interface

Abstract class can contain all types

of members such as data members,
methods, properties, constructors
etc. & also abstract methods.

Can have only abstract methods &

property declarations.

A child class can�t inherit multiple

abstract classes.

A child class can inherit (implement)

multiple interfaces

Abstract class can�t act as a

mediator between two classes.

Interface act as a mediator between

two classes.

In one class, we will implement in the

interface. In the other class, we will
create a reference variable for the
interface & call the methods.

Use abstract class, if you want to

provide a list of non-abstract
methods and abstract methods to
the child classes.

Use interface, if you want to provide

only a list of abstract methods to the
child classes.
5

Use abstract class, if you want to

create a �partial generic type�.

Ex: �Vehicle� is an abstract class,

which provides common methods
to all of its child classes such as
�Car�, �Bike�, and �Bus� etc.

Here the �Vehicle� class contains

both non-abstract (normal)
methods and also abstract
methods.

Use interface, if you want to create

pure �generic type�.

Ex: �IHolidayTrip� is an interface, which

provides common abstract methods to
all of its child classes such as
�FamilyHolidayTrip�,
�CollegeHolidayTrip� and
�CompanyHolidayTrip�.

If �CompanyHolidayTrip� is an abstract
(parent) class, �TCSHolidayTrip�,
�WiproHolidayTrip� etc., are the child
classes.

Observation:

� �IHolidayTrip� is pure general-

purpose. It doesn�t matter,
whether it is college holiday trip
or company holiday trip. It just
provides a list of common
methods of all types of holiday
trips.

� �CompanyHolidayTrip� is partial
general-purpose. It provides the
list of methods that are
common for all company
holiday trips; but it doesn�t
matter which company holiday
trip it is.
� Syntax to create an interface:

interface Interfacename

Declare interface methods here

� Syntax to create a child class for the interface:

class Classname : Interfacename

Implement all the interface methods here

}
Interfaces - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InterfacesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InterfacesExample�.
� Click on OK.

Program.cs

//interface

interface Interface1

//abstract methods

void Display();

//child class

class Class1 : Interface1

//Method Overriding: This method overrides (implements) the

"Interface1.Display" method. Both methods are having the same signature.

public void Display()

System.Console.WriteLine("Class1.Display");

}
class Program

static void Main()

Class1 p;

p = new Class1();

p.Display();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Interfaces � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InterfacesExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InterfacesExample2�.
� Click on OK.

Program.cs

//interface

interface IPerson

//properties

string PersonName { get; set; }

string Gender { get; set; }

//abstract method

void Display();

//child class 1

class Student : IPerson

//properties

public string PersonName { get; set; }

public string Gender { get; set; }

public int StudentID { get; set; }

public int Marks { get; set; }

 //implementing the IPerson.Display method

public void Display()

System.Console.WriteLine("Student Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

System.Console.WriteLine("Student ID: " + StudentID);

System.Console.WriteLine("Student Marks: " + Marks);

//child class 2

class Employee : IPerson

//properties

public string PersonName { get; set; }

public string Gender { get; set; }

public int EmpID { get; set; }

public double Salary { get; set; }

//implementing the IPerson.Display method

public void Display()

System.Console.WriteLine("Employee Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

System.Console.WriteLine("Employee ID: " + EmpID);

System.Console.WriteLine("Employee Salary: " + Salary);

class Program

{
static void Main()

/********** creating object for child class 1 ***************/

Student s;

s = new Student();

s.PersonName = "Allen";
 s.Gender = "Male";

s.StudentID = 101;

s.Marks = 70;

s.Display();

System.Console.WriteLine("\n");

/********** creating object for child class 2 ***************/

Employee emp;

emp = new Employee();

emp.PersonName = "Jones";

emp.Gender = "Male";

emp.EmpID = 201;

emp.Salary = 7000;

emp.Display();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Dynamic Polymorphism in C#.NET

Dynamic Polymorphism using interfaces

� Polymorphism means "decision making". The compiler takes a decision;

which method has to be called. If the decision has been taken at compile-
time (before running), we can call it as "compile-time polymorphism". If the
decision would be taken at run-time (when we run the program), we can call
it as "run-time polymorphism".
� "Method overloading" is an example of "compile-time polymorphism".
� We can implement dynamic polymorphism with interfaces or abstract
classes.
� Steps implementation of dynamic polymorphism using
interfaces:
o First we have to create an interface with one or more methods.
o Next we have implement it in two child classes.
o Create a reference variable for the interface.
o Create an object for first child class; Assign its reference into interface�s
variable & call the method now. It calls the first child class�s method.
o Create an object for second child class; Assign its reference into
interface�s variable & call the method now. It calls the second child class�s
method.
o So, same statement is calling different methods in different situations,
right! This is called �dynamic polymorphism�.

Static Polymorphism (vs) Dynamic Polymorphism

Sl. No

Static Polymorphism

Dynamic Polymorphism

Also called as "compile-time

polymorphism" or "early binding".

Also called as "run-time

polymorphism" or "late binding".

Decision will be taken by the

compiler at compile-time.

Decision will be taken by the CLR at

run-time.

Implemented using "method

overloading".

Implemented using "abstract classes"

or "interfaces".
Dynamic Polymorphism - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DynamicPolymorphismExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DynamicPolymorphismExample�.
� Click on OK.

Program.cs

//interface

interface Interface1

//abstract method in interface

void Display();

//child class 1

class Class1 : Interface1

//Overriding the "Interface1.Display" method

public void Display()

System.Console.WriteLine("Class1.Display");

//child class 2
class Class2 : Interface1

//Overriding the "Interface1.Display" method

public void Display()

System.Console.WriteLine("Class2.Display");

class Program

static void Main()

//create a reference variable of interface type.

Interface1 i;

//create object for first child class

i = new Class1();

i.Display(); //It calls Class1.Display()

//create object for second child class

i = new Class2();

i.Display(); //It calls Class2.Display()

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Dynamic Polymorphism � Example 2

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DynamicPolymorphismExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DynamicPolymorphismExample2�.
� Click on OK.

Program.cs

//interface

interface IPerson

//properties

string PersonName { get; set; }

string Gender { get; set; }

//abstract method

void Display();

//child class 1

class Student : IPerson

//properties

public string PersonName { get; set; }

public string Gender { get; set; }

//implementing the IPerson.Display method

public void Display()

{
 System.Console.WriteLine("Student Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

//child class 2

class Employee : IPerson

//properties

public string PersonName { get; set; }

public string Gender { get; set; }

//implementing the IPerson.Display method

public void Display()

System.Console.WriteLine("Employee Name: " + PersonName);

System.Console.WriteLine("Gender: " + Gender);

class Program

static void Main()

//create reference variable of interface type

IPerson p;

/************* creating object for child class 1 ***************/

p = new Student();
p.PersonName = "Allen";

p.Gender = "Male";

p.Display(); //calls Student.Display

System.Console.WriteLine("\n");

/************* creating object for child class 2 ***************/

 p = new Employee();

p.PersonName = "John";

p.Gender = "Male";

p.Display(); //calls Employee.Display

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Multiple Inheritance in C#.NET

Multiple Inheritance using Interfaces

� Interface supports �multiple inheritance�. That means a child class can

implement one or more interfaces. Then we must implement (define) all the
methods of all the interfaces in the same child class.
� Then you can store the address of class�s object in any reference variable of
any of those interfaces.

� Syntax for multiple inheritance:

class Classname : Interface1, Interface2, �

Implement all the methods or all interfaces here

}
Multiple Inheritance - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MultipleInheritanceExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultipleInheritanceExample�.
� Click on OK.

Program.cs

//interface 1

interface Interface1

void Method1();

void Method2();

//interface 2

interface Interface2

void Method3();

void Method4();

//child class - that implements multiple interfaces. This is called "multiple

inheritance".

class Class1 : Interface1, Interface2

{
 public void Method1()

System.Console.WriteLine("Class1.Method1");

public void Method2()

System.Console.WriteLine("Class1.Method2");

public void Method3()

System.Console.WriteLine("Class1.Method3");

public void Method4()

System.Console.WriteLine("Class1.Method4");

class Program

static void Main()

//create reference variable & object for child class

Class1 c1;

c1 = new Class1();

//create a reference variable for Interface1

Interface1 i1;

//store the address of child class's object in the interface reference

variable
i1 = c1;

//call the Interface1's methods only

i1.Method1();

i1.Method2();
 System.Console.WriteLine();

//create a reference variable for Interface2

Interface2 i2;

//store the address of child class's object in the interface reference

variable

i2 = c1;

//call the Interface2's methods only

i2.Method3();

i2.Method4();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Interface Inheritance in C#.NET

Interface Inheritance

� An interface can inherit from another interface.

� Then the child class of child interface should implement all the methods of
parent interface & child interface.

� Syntax for interface inheritance:

interface ChildInterface : ParentInterface

}
Interface Inheritance - Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InterfaceInheritanceExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InterfaceInheritanceExample�.
� Click on OK.

Program.cs

//parent interface

interface Interface1

void Method1();

void Method2();

//child interface

interface Interface2 : Interface1

void Method3();

void Method4();

//child class - that implements multiple interfaces. This is called "multiple

inheritance".

class Class1 : Interface2

public void Method1()

{
System.Console.WriteLine("Class1.Method1");
 }

public void Method2()

System.Console.WriteLine("Class1.Method2");

public void Method3()

System.Console.WriteLine("Class1.Method3");

public void Method4()

System.Console.WriteLine("Class1.Method4");

class Program

static void Main()

//create reference variable & object for child class

Class1 c1;

c1 = new Class1();

//create a reference variable for Interface1

Interface1 i1;
 //store the address of child class's object in the interface reference
variable

i1 = c1;

//call the Interface1's methods only

i1.Method1();
 i1.Method2();

System.Console.WriteLine();

//create a reference variable for Interface2

Interface2 i2;

//store the address of child class's object in the interface reference

variable

i2 = c1;

//call the Interface2's methods only

i2.Method3();

i2.Method4();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Principles of Object Oriented Programming

Principles of OOP

� OOP following the following principles.

1) Encapsulation
2) Hiding
3) Abstraction
4) Inheritance
5) Polymorphism

1) Encapsulation:
� Encapsulation is a concept of combining data members and methods
as a single unit called �object�.
� This is implemented by creating classes with data members and
methods.
� Data members are variables that stores the data; Methods are
functions that manipulates the data.
2) Hiding:
� Hiding is a concept of hiding private data to other classes.
� This is implemented by making some data members and methods
private.

3) Abstraction:
� Abstraction is a concept of hiding implementation details (internal
logic) and providing only necessary details to other classes.
� This is implemented by creating private data members and public
methods.

4) Inheritance:
� Inheritance is a concept of creating �parent-child� relationship among
two or more classes.
� As a result of inheritance, all the members of parent class are
accessible in child class.

5) Polymorphism:
� Polymorphism means "decision making".
� Polymorphism means �the ability of a statement that calls different
methods at different situations�.
� Types of polymorphism:
A. Static polymorphism (or) Compile-time polymorphism (or)
Early binding:
. Static polymorphism means method overloading.
. Method overloading is a concept of creating multiple methods
with same name in the same class with different types of
arguments. While calling the method, the matching method
will be executed, depending on the arguments that are
passed.
. The decision of which method is to be executed will be taken
at compilation time (by c#.net compiler). That�s why it is called
�Compile-time polymorphism�.
. Example of static polymorphism: Method overloading

B. Dynamic polymorphism (or) Run-time polymorphism (or) Late

binding:
. Dynamic polymorphism means method overriding.
. Method overriding is a concept of creating two methods with
same name and same signature; one is in parent class and
other one is in child class; both methods have different code.
. You will create a reference variable for the parent class (or)
interface; assign the reference of child class�s object; and call
the method. Then the current child class�s method will be
called.
. The decision of which class�s method is to be executed will be
taken at run time (by .net CLR). That�s why it is called �Run-
time polymorphism�.
. Example of dynamic polymorphism: Reference variable of
interface type.
Sealed Classes in C#.NET

Sealed Classes

� Sealed classes can�t be inheritable.

� If you don�t want to allow your class to be inheritable by others, you can
make it as sealed class.
� Sealed classes can contain any members just like normal classes.
� Syntax:

sealed class Classname

Any members here

Normal Class (vs) Sealed Class

Sl.
No

Normal Class

Sealed Class

Can be inherited.

Can't be inherited.
Sealed Classes - Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SealedClassesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SealedClassesExample�.
� Click on OK.

Program.cs

//sealed class

sealed class Class1

//we can't inherit from "Class1"

class Class2 : Class1

class Program

static void Main()

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: You will get compile time error near �Class2�.

Namespaces in C#.NET

Namespaces

� Namespaces are collections of �types�, such as classes, structures,

enumerations, interfaces and delegate types.
� The type that is present inside the namespace can be accessed by using
�Namespacename.Typename� syntax.
� Namespaces are used to group-up the types that belongs to a module or a
section of the project.
� Syntax:

namespace Namespacename

Classes, Structures, interfaces, Enumerations here

}
Namespaces - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �NamespacesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NamespacesExample�.
� Click on OK.

Program.cs

namespace Namespace1

class Class1

public void Method1()

System.Console.WriteLine("Namespace1.Class1.Method1");

namespace NamespacesExample

class Program

static void Main()

//create a reference variable

Namespace1.Class1 c1;
 //create an object

c1 = new Namespace1.Class1();

//call the method

c1.Method1();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Child Namespaces in C#.NET

Child Namespaces

� A namespace inside another namespace is called as �child namespace�.

� You can access the child namespace by using
�ParentNamespace.ChildNamespace� syntax.
� You can access the types of child namespace by using
�ParentNamespace.ChildNamespace.Typename� syntax.
� Syntax:

namespace ParentNamespacename

namespace ChildNamespacename

Types (Classes, structures etc.)

}
Child Namespaces - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ChildNamespacesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ChildNamespacesExample�.
� Click on OK.

Program.cs

//outer namespace starts

namespace ICICIBank

//inner namespace starts

namespace SavingsBanking

//class starts

class BankAccount

public void Deposit()

System.Console.WriteLine("ICICIBank.SavingsBanking.BankAccount.Deposit");

//class ends

//inner namespace ends

}

//outer namespace ends

namespace ChildNamespacesExample

class Program

static void Main()

//create a reference variable for BankAccount class

ICICIBank.SavingsBanking.BankAccount c1;

//create an object for BankAccount class

c1 = new ICICIBank.SavingsBanking.BankAccount();

//call the method

c1.Deposit();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Child Namespaces � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ChildNamespacesExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ChildNamespacesExample2�.
� Click on OK.

Program.cs

//Create a child namespace called "SavingsBanking" in a parent namespace

called "ICICIBank"

namespace ICICIBank.SavingsBanking

class BankAccount

public void Deposit()

System.Console.WriteLine("ICICIBank.SavingsBanking.BankAccount.Deposit");

namespace ChildNamespacesExample2

class Program

{
 static void Main()

//create reference variable

ICICIBank.SavingsBanking.BankAccount c1;

//create object

c1 = new ICICIBank.SavingsBanking.BankAccount();

//call method

c1.Deposit();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�using� statement in C#.NET

Using

� The �using� statement is used to import a namespace in the file.

� When you import a namespace, you can access all its members (classes,
structures etc.) directly, without writing the namespace name every time.
� Syntax:

using Namespacename;
�using� statement - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �UsingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �UsingExample�.
� Click on OK.

Program.cs

//import the namespace

using ICICIBank.SavingsBanking;

//create a child namespace called "SavingsBanking" in a parent namespace

called "ICICIBank"

namespace ICICIBank.SavingsBanking

class BankAccount

public void Deposit()

System.Console.WriteLine("ICICIBank.SavingsBanking.BankAccount.Deposit");

namespace UsingExample
{

class Program

static void Main()

//create reference variable; access "BankAccount" class directly, as it

is already imported above.

BankAccount c1;

//create object; access "BankAccount" class directly, as it is already

imported above.

c1 = new BankAccount();

//call the method

c1.Deposit();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�using - alias� statement in C#.NET

Using Alias

� It is used to create a �nick name� for a namespace, for easy access.

� You can access all the namespace�s members, by using the nickname.
� Syntax:

using Nickname = Namespacename;

�using - alias� statement - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �UsingAliasExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �UsingAliasExample�.
� Click on OK.

Program.cs

//creating alias name

using i = India;

using p = Pakisthan;

namespace India

class Hyderabad

public void City()

System.Console.WriteLine("India.Hyderabad");

namespace Pakisthan

class Hyderabad
 {

public void City()

System.Console.WriteLine("Pakisthan.Hyderabad");

namespace UsingAliasExample

class Program

static void Main()

i.Hyderabad h1 = new i.Hyderabad();

p.Hyderabad h2 = new p.Hyderabad();

h1.City();

h2.City();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Creating Separate Files for Classes in
C#.NET

Separate Files

� In realtime applications, it is recommended to create a class in its own

separate file, instead of creating all the classes in the same file.
� Class files make the large project easy to understand and maintain.
� Each class file�s extension should be �.cs�.
� A project can have any no. of class files.
� To add a class file, open the solution explorer; right click on the project
name and click on �Add� � �New Item�; select �Class�; type the class name as
�Filename.cs�; click on �Add�.
Creating Separate Files for Classes -
Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SeparateFilesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SeparateFilesExample�. Click on OK.
� Open Solution Explorer. Right click on the project name
(SeparateFilesExample) and click on �Add� � �New Item�. Click on �Code� �
�Class�. Type the file name as �BankAccount.cs�. Click on �Add�. Then it
creates the file �BankAccount.cs� in solution explorer.

BankAccount.cs

//Create a child namespace called "SavingsBanking" in a parent namespace

called "ICICIBank"

namespace ICICIBank.SavingsBanking

class BankAccount

public void Deposit()

System.Console.WriteLine("ICICIBank.SavingsBanking.
BankAccount.Deposit");

}
Program.cs

namespace mynamespace

class Program

static void Main()

//create reference variable

ICICIBank.SavingsBanking.BankAccount c1;

//create object

c1 = new ICICIBank.SavingsBanking.BankAccount();

//call the method

c1.Deposit();

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Partial Classes in C#.NET

Partial Classes

� Partial classes are used to split a large class into multiple files.
� In real time, one part of the class will be created by one programmer and
other part of the class will be created by other programmer; sometimes one
part of the class will be automatically generated by visual studio and other
part of the class will be created by the programmer.
� All the partial classes that should have a same name, should have �partial�
keyword, and should be inside a same namespace.

� Syntax to create a partial class:

partial class Classname

Members here

}
Partial Classes - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �PartialClassesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �PartialClassesExample�.
� Click on OK.
� Open Solution Explorer. Right click on the project and click on �Add� � �New
Item�. Select �Class�. Type the file name as �File1.cs�. Click on �Add�.
� Open Solution Explorer. Right click on the project and click on �Add� � �New
Item�. Select �Class�. Type the file name as �File2.cs�. Click on �Add�.

File1.cs

//create a parent namespace called "ICICIBank" and create a child

namespace called "SavingsBanking" in the parent namespace

namespace ICICIBank.SavingsBanking

//create a class called "BankAccount" in "ICICIBank.SavingsBanking"

namespace. This is a partial class. So at compilation time, the code for
File2.cs also will be combined with this class.

partial class BankAccount

//data members

public int accountnumber = 1234;

public string accountholdername = "John";

public double currentbalance = 10000;

//Deposit method
 public void Deposit(double amount)

currentbalance = currentbalance + amount;

File2.cs

//create a parent namespace called "ICICIBank" and create a child

namespace called "SavingsBanking" in the parent namespace

namespace ICICIBank.SavingsBanking

//Continue the definition of "BankAccount" class, which is defined at

"File1.cs".

partial class BankAccount

//Withdraw method

public void Withdraw(double amount)

currentbalance = currentbalance - amount;

}
Program.cs

namespace PartialClassesExample

class Program

static void Main()

//create reference variable

ICICIBank.SavingsBanking.BankAccount c1;

//create object

c1 = new ICICIBank.SavingsBanking.BankAccount();

//get current balance

System.Console.WriteLine(c1.currentbalance);

System.Console.ReadKey();

//deposit

c1.Deposit(5000);

System.Console.WriteLine(c1.currentbalance);

System.Console.ReadKey();

//withdraw

c1.Withdraw(2000);

System.Console.WriteLine(c1.currentbalance);

System.Console.ReadKey();

}
}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

After Pressing Enter

After Pressing Enter

Enumerations in C#.NET

Enumerations

� Enumerations are used to avoid the entry of wrong values into the variable.
It allows any one of the specific list of values.
� Enumeration is a collection of constants; each constant is assigned to an
integer value automatically (Starts with zero (0) by default).
� Based on enumeration, we can create enumeration variables (as a data
member or local variable).
� Enumeration variables can store any one of the enumeration constant.
� Syntax to create enumeration:

enum Enumerationname

Constant1, Constant2, �

}
Enumerations - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EnumerationExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EnumerationExample�.
� Click on OK.

Program.cs

using System;

//create a namespace called "EnumerationExample"

namespace EnumerationExample

//create an enumeration called "GenderEnumeration" inside a namespace

called "EnumerationExample"

enum GenderEnumeration

Male, Female

//create a class called "Person"

class Person

//data member of "String" data type

public string PersonName;

//data member of "GenderEnumeration" data type. This data member

can accept any one of the constants defined at GenderEnumeration only.

public GenderEnumeration Gender;

}
 class Program

static void Main()

//create reference variable of Person type

Person p;

//create an object of Person type

p = new Person();

//set data into PersonName

p.PersonName = "Scott";

//set data into "Gender". It accepts "Male" or "Female" only, as it is

"GenderEnumeration" type.

p.Gender = GenderEnumeration.Male;

//get data from data members

Console.WriteLine(p.PersonName);

Console.WriteLine(p.Gender);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Structures in C#.NET

Structures

� Structure is type (data type), which is a collection of members such as data

members, methods, constructors, properties etc., similar to classes.
� No memory will be allocated for structure. We can create "structure
variables" (instance) based on structure. For structure variables only
memory will be allocated. �Structure variable� stores actual data.

� Syntax to create structure:

struct Structurename

Data members, methods, constructors, properties etc.

Similarities between Classes and Structures

Sl. No

Class

Structure

Class is also a collection of

members like data members,
methods, constructors and
properties etc.

Structure is a collection of members

like data members, methods,
constructors and properties etc.

A class is a data type.

A structure is a data type.

Differences between Classes and Structures

Sl.
No

Class

Structure

An instance of class s called as

�object�.

�Object� are stored in �heap�.

�Instance of structure� is called as

�structure variable�.

�Structure variables� are stored in

�stack�.

We can create a reference variable

based on class.

We can�t create a reference variable

based on structure.

Classes are �reference-type� data

types; because �objects� are stored
in heap and its reference (address)
will be stored in stack.

Structures are �value-type� data types;

because �structure variables� (data)
directly will be stored in stack; there is
no �reference� (address) concept for
structures.

Classes are little bit slower than

structures; because to reach an
object, we have to go through
stack and find out the object based
on the address stored in the
reference variable.

Structures are little bit faster than

classes; because to reach a structure
variable, there is no need to search for
the address.

5
Classes support �inheritance� and
many other concepts.

Structures doesn�t support inheritance

and its related concepts.

Classes are suitable for creating

complex data structures &
methods.

Structures are suitable for creating

simple data structures.

�String�, �StringBuilder� etc., are

pre-defined classes.

All standard data types (except

�string�), such as int, float, double,
DateTime etc., are structures.

Classes supports both �parameter-

less constructor� and also
�parameterized constructor�.

Structures doesn�t support �parameter-

less constructor�; but supports
�parameterized constructor�.

The following syntax creates a

reference variable for the class:

Classname referencevariable;

The following syntax creates a structure

variable (instance) for the structure.

Structurename Structurevariable;
10

The following syntax creates an

object (instance) for the class &
also initializes all the data
members of the object:

new classname();

If the data member is numerical

data type, it initializes zero (0). If
the data member is string data
type, it initializes null. If the data
member is bool data type, it
initializes �false�.

The following syntax will not create an

instance, but initializes all the data
members of structure variable
(instance).

new structurename();

If the data member is numerical data

type, it initializes zero (0). If the data
member is string data type, it initializes
null. If the data member is bool data
type, it initializes �false�.
Structures - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StructuresExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StructuresExample�. Click on OK.

Program.cs

using System;

namespace StructuresExample

//create structure called "Student"

struct Student

//data members in structure

public int studentid;

public string studentname;

public int marks;

class Program

static void Main()

//create structure variable (instance)

Student s;
//set data into data members of structure variable
 s.studentid = 1;

s.studentname = "Scott";

s.marks = 70;

//get data from data members of structure variable

Console.WriteLine(s.studentid);

Console.WriteLine(s.studentname);

Console.WriteLine(s.marks);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Structures with Constructors - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StructuresWithConstructorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StructuresWithConstructorsExample�.
� Click on OK.

Program.cs

using System;

namespace StructuresWithConstructorsExample

//creating a structure

struct Student

//data members in structure

public int studentid;

public string studentname;

public int marks;

public string grade;

//constructor in structure

public Student(int value1, string value2, int value3)

studentid = value1;

studentname = value2;
marks = value3;

grade = "none";

//method in structure

public void CalculateGrade()

if (marks >= 80 && marks <= 100)

grade = "A grade";

else if (marks >= 60 && marks < 80)

grade = "B grade";

else if (marks >= 50 && marks < 60)

grade = "C grade";

else if (marks >= 35 && marks < 50)

grade = "D grade";

else if (marks < 35)

grade = "Fail";

class Program

static void Main()

//create structure variable (instance)

Student s;

//call the constructor

s = new Student(1, "Scott", 75);

//get data from data members of structure variable

Console.WriteLine("Student ID: " + s.studentid);

Console.WriteLine("Student name: " + s.studentname);

Console.WriteLine("Marks: " + s.marks);

 //call method

s.CalculateGrade();

Console.WriteLine("Grade: " + s.grade);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Standard Data Types

Standard Data Types are Structures / Classes

� All the standard data types are structures / classes.

Sl. No

Standard Data Type

Structure / Class

sbyte

struct SByte

byte

struct Byte

short

struct Int16

ushort

struct UInt16

int

struct Int32

uint

struct UInt32

long

struct Int64

8
ulong

struct UInt64

float

struct Single

10

double

struct Double

11

decimal

struct Decimal

12

char

struct Char

13

string

class String

14

bool

struct Boolean

15

DateTime

struct DateTime
The "System.Object" class in C#.NET

The �object� data type & �System.Object� class

� The "object" data type is an alias (nick) name of "System.Object" class.

� The "System.Object" is ultimate base class in .net, based on which all
structures and classes are inherited from.
� When you create a class in .net, automatically it will be treated as child class
of the parent class called �System.Object�.
�System.Object� Class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ObjectClassExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ObjectClassExample�.
� Click on OK.

Program.cs

using System;

namespace ObjectClassExample

class Class1

class Program

static void Main()

//create a reference variable of "System.Object" type

System.Object a;

//create an object of "Class1" and store its address in the reference

variable

a = new Class1();
 Console.WriteLine("Done");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Methods of "System.Object" class

Methods of �System.Object� class

� The �System.Object� class is a parent class to all classes and structures in

.net.
� The �System.Object� class provides the following methods to all classes and
structures:
A. bool Equals(Other Object)
. The Equals() method compares the actual object and other
object whether both are equal; It returns true if both are equal.
It returns false if both are not equal.

B. int GetHashCode()
. The GetHashCode() method returns the memory address of
the actual object.

C. Type GetType()
. The GetType() method returns the class name or structure
name to which the actual object belongs to.

D. string ToString()
. The ToString() method returns the class name or structure
name to which the actual object belongs to (similar to GetType
method). But it can be overridden in the child class. If it is
overridden, the child class�s method will run.
Methods of �System.Object� class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ObjectClassMethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ObjectClassMethodsExample�.
� Click on OK.

Program.cs

using System;

namespace ObjectClassMethodsExample

//"Class1" is child class of "System.Object" class automatically

class Class1

//override the ToString() method, which is the virtual method in

System.Object class

public override string ToString()

System.Console.WriteLine(base.GetHashCode());

return "Class1.ToString";

class Program

{
 static void Main()

//create two reference variables for Class1

Class1 c1, c2;

//create two objects for Class1

c1 = new Class1();

c2 = new Class1();

//call Equals method. This method compares whether c1 and c2 are

equal.

bool b = c1.Equals(c2);

Console.WriteLine(b);

//call GetHashCode method. This method returns the memory

address of the object.

int c = c1.GetHashCode();

Console.WriteLine(c);

//call GetType method. This method returns the type (class name) of
the object.

string t = c1.GetType().ToString();

Console.WriteLine(t);

//call ToString method. This method will call "ToString()" method,

which is defined in "Class1".

string s = c1.ToString();

Console.WriteLine(s);

Console.ReadKey();

}
 }

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Boxing in C#.NET

Boxing

� It is a process of converting a value from "value-type data type (any

structure)" to "reference-type data type (System.Object class)".
� It will be done automatically.

Syntax: ReferenceTypeVariable = ValueTypeVariable ;

Boxing - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �BoxingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �BoxingExample�.
� Click on OK.

Program.cs

using System;

namespace BoxingExample

class Program

static void Main()

//creating a variable of "int" data type. "int" is a "structure". All the

structures "value-type data types".

int a = 1000;

//creating a reference variable of "System.Object" data type.

"System.Object" is a class. All the classes are "reference-type data types".

System.Object obj;

//Automatic conversion from "int" structure to "System.Object" class.

This is called boxing.

obj = a;
 //get values

Console.WriteLine(a); //Output: 1000

Console.WriteLine(obj); //Output: 1000

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Unboxing in C#.NET

Unboxing

� It is a process of converting a value from "reference-type data type

(System.Object)" to "value-type data type (any structure)". It should be done
manually, by using �type casting� syntax.

Syntax: ValueTypeVariable = (ExpectedDataTypehere)ReferenceTypeVariable;

Unboxing - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �UnboxingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �UnboxingExample�.
� Click on OK.

Program.cs

using System;

namespace UnboxingExample

class Program

static void Main()

//create a reference variable of "System.Object" data type.

"System.Object" is a class; All the classes are "reference-type" data type.

Object obj = 100;

//create a variable of "int" data type. "int" is a structure. All the

structures "value-type" data type.

int a;

//manual conversion from "System.Object" class to "int" structure.

This is called "unboxing".
 a = (int)obj;

//get values

Console.WriteLine(obj); //Output: 100

Console.WriteLine(a); //Output: 100

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Static Data Members in C#.NET

Static Data Members

� Static data members are used to common data that belongs to all the
objects. Non-Static Data members are stored in the objects; Static data
members are stored outside the objects. Static members are not accessible
with reference variable, but accessible with �class name�.
� Data members are two types:
1. Non-static data members (or) instance data members
2. Static data members (or) shared data members

Sl.
No

Non-Static Data Members

Static Data Members

By default, all the data members are

non-static data members. These are
not created with a keyword called
�static�.

Static data members are created using

�static� keyword.

Non static data members are stored in

the object. That means when you
create an object for the class, the
memory will be allocated for all the
non-static data members in the object.

For static data members, memory will not

be allocated in the object. When you
access the class name for the first time in
the main method, then memory will be
allocated for the static data members.

Non-static data member�s memory will

be allocated separately for every
object of the class.

Static data member�s memory will be

allocated only once for entire project.
4

Non-static data members accessible

with reference variable.

Static data members are accessible with

class.

If you don�t create an object for the

class, no memory will be allocated for
non-static data member.

If you don�t access the class in the entire

program, no memory will be allocated for
static data members.

Use non-static data members if you

want to store object-specific data
(which is different for each object).

Use static data members if you want to

store common data that belongs to all
the objects.
Static Data Members - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StaticDataMembersExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StaticDataMembersExample�.
� Click on OK.

Program.cs

using System;

namespace StaticDataMembersExample

//creating a class called "Student".

class Student

//instance data members (or) non-static data members

public int studentid;

public string studentname;

public int marks;

//static data member (or) shared data member

public static string collegename;

class Program

static void Main()

{
//create two reference variables

Student s1;

Student s2;

//create two objects

s1 = new Student();

s2 = new Student();

//set data into members of s1

s1.studentid = 1;

s1.studentname = "scott";

s1.marks = 70;

//set data into members of s2

s2.studentid = 2;

s2.studentname = "allen";

s2.marks = 80;

//get data from members of s1

Console.WriteLine("Student ID: " + s1.studentid);

Console.WriteLine("Student Name: " + s1.studentname);

Console.WriteLine("Marks: " + s1.marks);

Console.WriteLine();

//get data from members of s2

Console.WriteLine("Student ID: " + s2.studentid);

Console.WriteLine("Student Name: " + s2.studentname);

Console.WriteLine("Marks: " + s2.marks);

Console.WriteLine();
//set data into static data member

Student.collegename = "ABC college of technology";

//get data from static data member

Console.WriteLine("College Name: " + Student.collegename);

 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Static Constructors in C#.NET

Static Constructors

� Non-static constructors (normal constructors) initialize non-static data

members and static data members; Static constructors initialize static data
members only. Static constructors will be called automatically when the
class is used for the first time in Main method.
� Constructors are two types:
1. Non-static constructors (or) instance constructors
2. Static constructors (or) shared constructors

Sl. No

Non-Static Constructors

Static Constructors

By default, all the constructors are

non-static constructors. These are
not created with a keyword called
�static�.

Static constructors are created

using �static� keyword.

Non-static constructors can access

both non-static members and non-
static members.

Static constructors can access only

static members. Static constructors
can�t access non-static members.
However, if you create an object
for the class in the static
constructor, then you can access
any non-static members though the
object, in the static constructor.

Non-static constructors are

accessible with object only. When
you create an object for the class, it
calls the non-static constructor
automatically. Non-static
constructors are not accessible
without creating an object for the
class.

Static constructor will be called

automatically when you access the
class name for the first time in the
Main method.
4

Non-static constructor will be

called every time when we create
an object for the class.

Static constructor will be called

only once in the entire program.

We can use �this� keyword in the

non-static constructors, because
non-static constructors are called
with an object.

We can�t use �this� keyword in the

static constructor, because static
constructor is called with class only,
without an object.

A class can have �n� no. of non-

static constructors.

A class can have only one static

constructor.

Use non-static constructors, if you

want to initialize non-static data
members.

Use static constructor if you want

to initialize static data members.

Non-static constructors can receive

�n� no. of arguments.

Static constructor can�t receive any

arguments.

Non-static constructors can�t

return any value.

Static constructor also can�t return

any value.

10

Access modifier such as �internal�

and �public� can be applicable for
the non-static constructor.

Access modifier is not applicable

for the static constructor. By
default, they are �public�.
Static Constructors - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �StaticConstructorsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StaticConstructorsExample�. Click on OK.

Program.cs

using System;

namespace StaticConstructorsExample

//creating a class called "Class1"

class Class1

//static data members

public static int a, b;

//static constructor. It initializes the static data members

static Class1()

a = 10;

b = 20;

class Program

{
static void Main()
 {

//Note: static constructor will be automatically called here

//get data from static data members

Console.WriteLine(Class1.a); //Output: 10

Console.WriteLine(Class1.b); //Output: 20

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Static Methods in C#.NET

Static Methods

� Non-static methods are used to manipulate non-static data members; Static

methods are used to manipulate static data members only. Static methods
can be called with class name only.
� Methods are two types:
1. Non-static methods (or) instance methods
2. Static methods (or) shared methods

Sl.
No

Non-Static Methods

Static Methods

By default, all the methods are

non-static methods. These are
not created with a keyword
called �static�.

Static methods are created using �static�

keyword.

Non-static methods can access

both non-static members and
non-static members.

Static methods can access only static

members. Static methods can�t access
non-static members. However, if you
create an object for the class in the static
methods, then you can access any non-
static members though the object, in the
static method.

Non-static methods are

accessible with object only. Non-
static methods are not accessible
without creating an object for
the class.

Static methods are accessible with class

only. Static methods are accessible
without creating an object for the class.
Static methods are not accessible with an
object.
4

We can use �this� keyword in the

non-static methods, because
non-static methods are called
with an object.

We can�t use �this� keyword in the static

methods, because static methods are
called with class only, without an object.
5

Use non-static methods, if you

want to perform some operation
based on non-static data
members.

Use static data members if you want to

perform some operation based on static
data members.
Static Methods - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �StaticMethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StaticMethodsExample�.
� Click on OK.

Program.cs

using System;

namespace StaticMethodsExample

//creating a class called "Class1"

class Class1

//static data members

public static int n, sum;

//static method. This method performs manipulations on static data

members

public static void CalculateSumOfnNaturalNumbers()

for (int i = 1; i <= n; i++)

sum += i;

class Program
 {

static void Main()

//Note: .NET allocates memory for static data members automatically

here.

//set value into static data member

Class1.n = 10;

//call static method

Class1.CalculateSumOfnNaturalNumbers();

//get data from static data member

Console.WriteLine("Sum: " + Class1.sum); //Output: 55

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Static Classes in C#.NET

Static Classes

� Static classes can contain only static members (static data members, static
methods, static constructors, static properties etc.).
� Static classes can�t contain non-static members.
� We can�t create an object for static class.
� Syntax to create static class:

static class Classname

Only static members here

Normal Class (vs) Static Class

Sl. No

Normal class

Static class

No "static" keyword.

Should have "static" keyword.

Can have both non-static

members and static members
also.

Can have only static members.

We can create an object for

normal class.

We can't create an object for static

class.
Static Classes - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StaticClassesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StaticClassesExample�.
� Click on OK.

Program.cs

using System;

namespace StaticClassesExample

//static class. A static class contains only static data members, static
properties, static constructors, and static methods only

static class Class1

//static data member

public static string _Message;

//static properties

public static string Message

set

_Message = value;

}
 get

return _Message;

//static constructor

static Class1()

Message = "Hello";

//static method

public static void Method1()

Console.WriteLine("Class1.Method1");

class Program

static void Main()

//Note: .NET automatically allocated memory for static data member

here

//Note: static constructor will be called automatically here

//get value from static property

Console.WriteLine(Class1.Message);
//call static method

Class1.Method1();

Console.ReadKey();

}
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Constant Data Members in C#.NET

Constant data members

� Constant data member�s value can�t be changed in the rest life of the object.
� Constant data members must be initialized along with the declaration.
Those can�t be initialized in the constructor.
� Constant data members are created using �const� keyword.
� Constant data members are by default �static�; so they are accessible
without creating an object for the class, using class name.
� Syntax:

Accessmodifier const Datatype Constantname = value;

Constant Data Members - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConstantsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConstantsExample�.
� Click on OK.

Program.cs

using System;

namespace ConstantsExample

class Class1

//'constant data member'. This is static by default.

public const int NoOfMonthsInYear = 12;

class Program

static void Main()

//get value from 'constant data member'

Console.WriteLine(Class1.NoOfMonthsInYear);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
ReadOnly Data Members in C#.NET

Read-only data members

� Read-only data members must be initialized along with the declaration or in

the constructor. It must be initialized before constructor ends.
� Read-only data member�s value can�t be changed in the rest life of the
object.
� Read-only data members are created using �readonly� keyword.
� Syntax:

Accessmodifier readonly Datatype Variablename;

Constant (vs) Readonly

Sl. No

Constant

Readonly

Declared with "const" keyword.

Declared with "readonly" keyword.

Can be created in a method or as

a data member.

Can be created as a data member

only.

Should be initialized along with

its declaration.

Should be initialized either along with

its declaration or in the constructor.

Useful to initialize a fixed value

only.

Useful to initialize fixed value or

result of a calculation.
ReadOnly Data Members - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ReadOnlyExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ReadOnlyExample�.
� Click on OK.

Program.cs

using System;

namespace ReadOnlyExample

class Class1

//readonly data member

public readonly int NoOfDaysInMonth;

//constructor

public Class1()

//get system year

int y = DateTime.Now.Year;

//get system month

int m = DateTime.Now.Month;
//create a local variable

int d;

//check

switch (m)

case 1: d = 31; break;

case 2: d = 28; break;

case 3: d = 31; break;

case 4: d = 30; break;

case 5: d = 31; break;

case 6: d = 30; break;

case 7: d = 31; break;

case 8: d = 31; break;

case 9: d = 30; break;

case 10: d = 31; break;

case 11: d = 30; break;

case 12: d = 31; break;

default: d = 0; break;

//check leap year

if (y % 4 == 0 && m == 2)

d = 29;

//set the value of "d" into "NoOfDaysInMonth" data member

NoOfDaysInMonth = d;

}
class Program

static void Main()

//create reference variable

 Class1 c1;

//create object

c1 = new Class1();

//get value from readonly data member

Console.WriteLine(c1.NoOfDaysInMonth);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Generic Classes in C#.NET

Generic Classes

� Generic class is a class, which contains one or more generic-type data

members.
� Generic classes let you to store different values with respective to different
objects in the same data members.
� Generic classes let you to decide the data type of a data member, while
creating object, rather than deciding the data type while creating the class.
� While creating an object for the generic class, you have to specify the data
type of a data member.
� While creating a re-usable class, instead of you decide the data type of a
data member within your class, if you want to let other programmers decide
the data type that they want, you can make your class as generic class and
make your data member as generic data member.

� Syntax to create generic class:

class Classname<T>

public T Datamembername;

}
Generic Classes - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �GenericsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �GenericsExample�.
� Click on OK.

Program.cs

using System;

namespace GenericsExample

//generic class with a generic-type parameter called "T"

class Class1<T>

//generic data member of generic-type called "T"

public T x;

class Program

static void Main()

//creating first generic object. As per this object "x" is of "int" data
type.

Class1<int> c1;

c1 = new Class1<int>();
 c1.x = 100;

Console.WriteLine(c1.x); //Output: 100

//creating second generic object. As per this object "x" is of "string"

data type.

Class1<string> c2;

c2 = new Class1<string>();

c2.x = "hello";

Console.WriteLine(c2.x); //Output: hello

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Multiple Generics - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MultipleGenericsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultipleGenericsExample�.
� Click on OK.

Program.cs

using System;

namespace MultipleGenericsExample

//generic class with two generic-type parameters called "T1" and "T2"

class Class1<T1, T2>

//generic data member of generic-type called "T1"

public T1 x;

//generic data member of generic-type called "T2"

public T2 y;

class Program

static void Main()

{
 //creating first generic object. As per this object "x" is of "int" data
type and "y" is of "bool" data type.

Class1<int, bool> c1;

c1 = new Class1<int, bool>();

c1.x = 100;

c1.y = true;

Console.WriteLine(c1.x); ; //Output: 100

Console.WriteLine(c1.y); ; //Output: true

Console.WriteLine();

//creating second generic object. As per this object "x" is of "string"

data type and "y" is of "double" data type.

Class1<string, double> c2;

c2 = new Class1<string, double>();

c2.x = "hello";

c2.y = 100.438;

Console.WriteLine(c2.x); //Output: hello

Console.WriteLine(c2.y); //Output: 100.438

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Arrays in C#.NET

Arrays

� An array is a collection of multiple values of same data type.

� For each element, system automatically maintains an index. The index
always starts from zero (0).
� Ex: Country names, City names, student marks etc.
� Syntax to create an array:

Datatype [ ] Arrayname = new Datatype [int length];

Arrays - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysExample

class Program

static void Main()

//create an array with 5 elements.

int[ ] a = new int[5] { 10, 20, 50, 80, 100 };

//get values from array, based on the index

Console.WriteLine(a[0]);

Console.WriteLine(a[1]);

Console.WriteLine(a[2]);

Console.WriteLine(a[3]);

Console.WriteLine(a[4]);

Console.WriteLine();
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Arrays with For Loop in C#.NET

Arrays with for loop

� We can read elements from an array, by using for loop:

� The for loop executes once for one element.
� Syntax to read all elements from an array using for loop:

for (int i=0; i < arrayname.Length; i++)

Code here

}
Arrays with For Loop - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithForExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithForExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithForExample

class Program

static void Main()

//create an array with 5 elements

int[ ] a = new int[5] { 10, 20, 50, 80, 100 };

//get values from array, using for loop

for (int i = 0; i < a.Length; i++)

Console.WriteLine(a[i]);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Arrays with Foreach Loop

in C#.NET

Arrays with Foreach loop

� �foreach� loop is used to read all the values from an array.

� It executes once for one element in the array. Each time, the current
element will be stored in the temporary variable.
� Syntax of foreach loop:

foreach (Datatype Variablename in Arrayname)

� But it is used to read all the values of an array, sequentially. It is not

possible
to read some of the values, by using �foreach� loop. It is also not possible to
read the elements randomly or in reverse order.
Arrays with Foreach Loop � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithForEachExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithForEachExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithForEachExample

class Program

static void Main()

//create an array with 5 elements

int[ ] a = new int[5] { 10, 20, 50, 80, 100 };

//get values from array, using foreach loop

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array� class in C#.NET

�System.Array� class

� The �System.Array� is a pre-defined class. An object of �System.Array� class

represents an array.
� In c#.net, every array is automatically treated as an object of �System.Array�
class. So we can call methods of �System.Array� class, by using any array.
� The �System.Array� class has the following methods:
1. System.Array.IndexOf()
2. System.Array.BinarySearch()
3. System.Array.Clear()
4. System.Array.Resize()
5. System.Array.Sort()
6. System.Array.Reverse()
7. System.Array.CopyTo()
�System.Array.IndexOf� method in C#.NET

Sl. No

Method

int System.Array.IndexOf(System.Array array, object value)

This method searches the array for the given value.

If the value is found, it returns its index.

If the value is not found, it returns -1.

array: This parameter represents the array, in which you want to search.

value: This parameter represents the actual value that is to be searched.

The �IndexOf� method performs linear search. That means it searches all
the elements of an array, until the search value is found. When the search
value is found in the array, it stops searching and returns its index.

The linear search has good performance, if the array is small. But if the
array is larger, Binary search is recommended to improve the performance.
�System.Array.IndexOf� method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithIndexOfExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithIndexOfExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithIndexOfExample

class Program

static void Main()

//create array with

int[ ] a = new int[5] { 100, 2000, 50, 8, 1000 };

//search (linear search) for "50" in array & get its index

int n = Array.IndexOf(a, 50);

Console.WriteLine(n); //Output: 2

Console.ReadKey();

}
}

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.IndexOf� method � with
NotFound - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithIndexOfWithNotFound�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithIndexOfNotFound�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithIndexOfWithNotFound

class Program

static void Main()

//create array

int[] a = new int[5] { 100, 2000, 50, 8, 1000 };

//search (linear search) for "500" in array & get its index. If not found,
it returns -1

int n = Array.IndexOf(a, 500);

Console.WriteLine(n);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.BinarySearch� method in
C#.NET

Sl. No

Method

int System.Array.BinarySearch(System.Array array, object

value)

This method searches the array for the given value.

If the value is found, it returns its index.

If the value is not found, it returns -1.

array: This parameter represents the array, in which you want to search.

value: This parameter represents the actual value that is to be searched.

The �BinarySearch� method performs binary search. The �Binary Search�

requires an array, which is already sorted. On unsorted arrays, binary
search is not possible.

Binary search means it directly goes to the middle of the array (array size /
2), and checks that item is less than / greater than the search value. If that
item is greater than the search value, it searches only in the first half of the
array. If that item is less than the search value, it searches only in the
second half of the array. Thus it searches only half of the array. So in this
way, it saves performance.
�System.Array.BinarySearch� method -
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithBinarySearchExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithBinarySearchExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithBinarySearchExample

class Program

static void Main()

//For Binary search, we must need a sorted array (should have the
values in ascending order)

int[ ] a = new int[5] { 10, 20, 50, 80, 100 };

//search (binary search) for "50" in sorted array & get its index

int n = Array.BinarySearch(a, 50);

Console.WriteLine(n);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.Clear� method in C#.NET

Sl. No

Method

void System.Array.Clear(System.Array array, int index, int

length)

This method starts with the given index and sets all the �length� no. of
elements to zero (0).

array: This parameter represents the array, in which you want to clear the
elements.

index: This parameter represents the index, from which clearing process is
to be started.

length: This parameter represents the no. of elements that are to be

cleared.
�System.Array.Clear� method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithClearExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithClearExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithClearExample

class Program

static void Main()

//create array

int[ ] a = new int[8] { 10, 20, 50, 80, 100, 780, 900, 1000 };

//set the 3 elements to zero (0), starting from index "2"

Array.Clear(a, 2, 3);

//get values from array

foreach (int item in a)

Console.WriteLine(item);

}
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.Resize� method in C#.NET

Sl. No

Method

void System.Array.Resize(ref System.Array array, int

newSize)

This method increases / decreases size of the array.

array: This parameter represents the array, which you want to resize.

newSize: This parameter represents the new size of the array, how many
elements you want to store in the array. It can be less than or greater than
the current size.
�System.Array.Resize� method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithResizeExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithResizeExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithResizeExample

class Program

static void Main()

//create array (current size of array is "4")

int[ ] a = new int[4] { 10, 20, 50, 80 };

//change size of the array from "4" to "6"

Array.Resize(ref a, 6);

a[4] = 200;

a[5] = 350;

//get values from array

foreach (int item in a)

{
 Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.Sort� method in C#.NET

Sl. No

Method

void System.Array.Sort(System.Array array)

This method sorts the array in ascending order.

array: This parameter represents the array, which you want to sort.
�System.Array.Sort� method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithSortExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithSortExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithSortExample

class Program

static void Main()

//create array

int[ ] a = new int[7] { 50, 20, 100, 30, 500, 150, 300 };

//sort the array

Array.Sort(a);

//get values from array

foreach (int item in a)

Console.WriteLine(item);
 }

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.Reverse� method in C#.NET

Sl. No

Method

void System.Array.Reverse(System.Array array)

This method reverses the array.

array: This parameter represents the array, which you want to reverse.
�System.Array.Reverse� method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithReverseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithReverseExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithReverseExample

class Program

static void Main()

//create array

int[ ] a = new int[7] { 50, 20, 100, 30, 500, 150, 300 };

//reverse the array

Array.Reverse(a);

//get values from the array

foreach (int item in a)

Console.WriteLine(item);
 }

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Array.CopyTo� method in C#.NET

Sl. No

Method

void sourceArray.CopyTo(System.Array destinationArray, int

startIndex)

This method copies all the elements from source array to destination array.

sourceArray: This parameter represents the array, which array you want to
copy.

destinationArray: This parameter represents the array, into which you

want to copy the elements of source array.

startIndex: This parameter represents the index of the element, from

which you want to start copying.
�System.Array.CopyTo� method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArraysWithCopyToExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArraysWithCopyToExample�.
� Click on OK.

Program.cs

using System;

namespace ArraysWithCopyToExample

class Program

static void Main()

//create array

int[] a = new int[5] { 10, 20, 50, 80, 100 };

//create another array

int[] b = new int[5];

//copy all the elements from one array to another array

a.CopyTo(b, 0);

//get values from array

 foreach (int item in b)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Multi-Dimensional Array in C#.NET

Multi-dimensional array

� Multi-dimensional arrays are used to store multiple values in a single row of

an array.
� Syntax to create multi-dimensional array:

Datatype[ , ] Arrayname = new Datatype[int rowLength, int

columnLength]

� Note: You can increase the no. of commas (,) as many as you want.
Multi-Dimensional Array - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �MultiDimArraysExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultiDimArraysExample�.
� Click on OK.

Program.cs

using System;

namespace MultiDimArraysExample

class Program

static void Main()

//create multi-dim array

int[,] a = new int[4, 3]

{ 10, 20, 30 },

{ 40, 50, 60 },

{ 70, 80, 90 },

{ 100, 110, 120 }

};

//get first row from multi-dim array

Console.Write(a[0, 0]);

Console.Write(" ");
 Console.Write(a[0, 1]);

Console.Write(" ");

Console.WriteLine(a[0, 2]);

//get second row from multi-dim array

Console.Write(a[1, 0]);

Console.Write(" ");

Console.Write(a[1, 1]);

Console.Write(" ");

Console.WriteLine(a[1, 2]);

//get third row from multi-dim array

Console.Write(a[2, 0]);

Console.Write(" ");

Console.Write(a[2, 1]);

Console.Write(" ");

Console.WriteLine(a[2, 2]);

//get fourth row from multi-dim array

Console.Write(a[3, 0]);

Console.Write(" ");

Console.Write(a[3, 1]);

Console.Write(" ");

Console.WriteLine(a[3, 2]);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Introduction to Collections in C#.NET

Limitations of arrays

� Adding or removing elements from array (without a duplicate copy) is not

possible.
� Solution: Use collections.

What are collections

� A collection is a "group of values" of same data type.

� We can add, remove values in the collection anywhere within the program.
� Collections internally use arrays, managed by some pre-defined methods.
� To create collections .net provides a set of collection classes.

� List of collections classes in .NET:

1. System.Collections.Generic.List
2. System.Collections.Generic.Dictionary
3. System.Collections.Generic.SortedList
4. System.Collections.Hashtable
5. System.Collections.ArrayList
Arrays (vs) Collections

Sl. No

Arrays

Collections

Array is treated as an object of

"System.Array" class.

Collection is treated as an object of

collection-based class such as
"System.Collections.Generic.List",
"System.Collections.Generic.Dictionary"
etc.

Doesn�t support adding,

removing elements
dynamically.

Support adding, removing elements

dynamically.

Arrays is old concept.

Collections are recommended and

mostly-used in real time.

If you want to store fixed no. of

values, then use "arrays".

If you want to add or remove elements

later, then use "collections".
The "List" class in .NET

System.Collections.Generic.List

� "List" is a class, in "System.Collections.Generic" namespace.

� This class�s object represents a collection.
� "List" is a collection-based class.
� List is used to store multiple values of same data type.
� We can add or remove elements in the collection dynamically.
� It is a generic class; it has a generic type argument called �T�. That means
you must pass a data type as argument to it, while creating an object.
The "List" class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ListExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 90, 100 };

//get values from list collection

Console.WriteLine(a[0]);

Console.WriteLine(a[1]);

Console.WriteLine(a[2]);

Console.WriteLine(a[3]);

Console.WriteLine(a[4]);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "List" class � with �for� loop in C#.NET

List with for loop

� We can read elements from a list collection, by using for loop:

� The �for loop� executes once for one element.
� Syntax to read all elements from the list collection, using for
loop:

for (int i = 0; i < collectionname.Count; i++)

Code here

}
The "List" class � with �for� loop - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ListWithForExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithForExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithForExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 90, 100 };

//get values from list collection using for loop

for (int i = 0; i < a.Count; i++)

Console.WriteLine(a[i]);

}
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "List" class � with �foreach� loop in
C#.NET

List with Foreach loop

� �foreach� loop is used to read all the values from a list collection.
� It executes once for one element in the collection. Each time, the current
element will be stored in the temporary variable.
� Syntax of foreach loop:

foreach (Datatype Variablename in Collectionname)

� But it is used to read all the values of a collection, sequentially. It is not

possible to read some of the values, by using �foreach� loop. It is also not
possible to read the elements randomly or in reverse order.
The "List" class � with �foreach� loop -
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ListWithForEachExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithForEachExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithForEachExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 90, 100 };

//get values from list collection using foreach loop

foreach (int item in a)

Console.WriteLine(item);

}
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.Add"
method in C#.NET

Sl. No

Method

void Add(object value)

This method adds a new value at the end of existing collection.

value: This parameter represents the actual value that is to be added.

"System.Collections.Generic. List.Add"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithAddExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithAddExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithAddExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50 };

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.WriteLine();

//add "100" at the end of list collection

a.Add(100);
 //get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List. Insert"
method in C#.NET

Sl. No

Method

void Insert(int index, object value)

This method inserts a new value at the specified index in the existing
collection.

index: This parameter represents the index, where the value is to be

inserted.

value: This parameter represents the actual value that is to be added.

"System.Collections.Generic. List.Insert"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithInsertExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithInsertExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithInsertExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 150, 200 };

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.WriteLine();
 //insert the value "100" at the position number "2"

a.Insert(2, 100);

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic.
List.AddRange" method in C#.NET

Sl. No

Method

void AddRange(collection)

This method adds an array or collection at the end of existing collection.

collection: This parameter represents the array / collection that is to be

added.
"System.Collections.Generic.
List.AddRange" method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ListWithAddRangeExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithAddRangeExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithAddRangeExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 150, 200 };

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

}
 Console.WriteLine();

//create another list collection called "extra"

List<int> extra = new List<int>() { 300, 400, 500 };

//add all the elements of "extra" collection at the end of "a" collection

a.AddRange(extra);

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic.
List.InsertRange" method in C#.NET

Sl. No

Method

void InsertRange(int index, collection)

This method inserts an array or collection at the specified index in the

existing collection.

index: This parameter represents the index, where the array / collection is
to be inserted.

collection: This parameter represents the array / collection that is to be

inserted.
"System.Collections.Generic.
List.InsertRange" method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ListWithInsertRangeExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithInsertRangeExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithInsertRangeExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 150, 200 };

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.WriteLine();

//create another collection called "extra"

List<int> extra = new List<int>() { 60, 70, 80 };

 //insert all the elements of "extra" collection into "a" collection at
position no. "3"

a.InsertRange(3, extra);

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.Remove"
method in C#.NET

Sl. No

Method

void Remove(object value)

This method removes the specified value in the end of existing collection.

value: This parameter represents the value that is to be removed.

"System.Collections.Generic. List.Remove"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithRemoveExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithRemoveExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithRemoveExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50 };

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.WriteLine();
 //remove "40" from the list collection

a.Remove(40);

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic.
List.RemoveAt" method in C#.NET

Sl. No

Method

void RemoveAt(int index)

This method removes the existing value at the specified index in the
existing collection.

index: This parameter represents the index, where the value is to be

removed.
"System.Collections.Generic.
List.RemoveAt" method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithRemoveAtExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithRemoveAtExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithRemoveAtExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 120, 200 };

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.WriteLine();
 //remove the element at position no. "2" in the collection

a.RemoveAt(2);

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.Clear"
method in C#.NET

Sl. No

Method

void Clear()

This method deletes all the elements in the existing collection.

"System.Collections.Generic. List.Clear"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithClearExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithClearExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithClearExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 10, 20, 50 };

//clear all items in the list collection

a.Clear();

//add new items into the list collection

a.Add(80);

a.Add(120);

a.Add(130);
 //get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.IndexOf"
method in C#.NET

Sl. No

Method

int IndexOf(object value)

This method searches the collection for the given value.

If the value is found, it returns its index.

If the value is not found, it returns -1.

value: This parameter represents the actual value that is to be searched.

The �IndexOf� method performs linear search. That means it searches all
the elements of the collection, until the search value is found. When the
search value is found in the collection, it stops searching and returns its
index.

The linear search has good performance, if the array is small. But if the
collection is larger, "Binary search" is recommended to improve the
performance.
"System.Collections.Generic. List.IndexOf"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ListWithIndexOfExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithIndexOfExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithIndexOfExample

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 120, 200 };

//search for "50" in the list collection & get its index

int n = a.IndexOf(50);

Console.WriteLine(n);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.IndexOf"
method � Not Found- Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithIndexOfNotFoundExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithIndexOfNotFoundExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithIndexOfNotFound

class Program

static void Main()

//create list collection

List<int> a = new List<int>() { 10, 40, 50, 120, 200 };

//search for "500" in the list collection & get its index

int n = a.IndexOf(500);

Console.WriteLine(n);

Console.ReadKey();

}
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic.
List.BinarySearch" method in C#.NET

Sl. No

Method

int BinarySearch(object value)

This method searches the collection for the given value.

If the value is found, it returns its index.

If the value is not found, it returns -1.

value: This parameter represents the actual value that is to be searched.

The �BinarySearch� method performs binary search. The �Binary Search�

requires a collection, which is already sorted. On unsorted collection,
binary search is not possible.

Binary search means it directly goes to the middle of the collection

(collection size / 2), and checks that item is less than / greater than the
search value. If that item is greater than the search value, it searches only
in the first half of the collection. If that item is less than the search value, it

searches only in the second half of the collection. Thus it searches only half
of the collection. So in this way, it saves performance.
"System.Collections.Generic.
List.BinarySearch" method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithBinarySearchExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithBinarySearchExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithBinarySearchExample

class Program

static void Main()

//list collection with sorted items (values should in a ascending order)

List<int> a = new List<int> { 10, 20, 50, 80, 100 };

//search for "50" in the collection

int n = a.BinarySearch(50);

Console.WriteLine(n);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.Contains"
method in C#.NET

Sl. No

Method

10

void Contains(object value)

This method searches the collection for the given value.

If the value is found, it returns true.

If the value is not found, it returns false.

value: This parameter represents the actual value that is to be searched.

"System.Collections.Generic. List.Contains"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithContainsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithContainsExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithContainsExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 10, 20, 50, 80, 100 };

//check whether the list has "50" or not

bool b = a.Contains(50);

Console.WriteLine(b);

Console.ReadKey();

}
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.Reverse"
method in C#.NET

Sl. No

Method

12

void Reverse()

This method reverses the collection.

"System.Collections.Generic. List.Reverse"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithReverseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithReverseExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithReverseExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 50, 20, 100, 30, 500, 150, 300 };

//reverse the collection

a.Reverse();

//get values from the list collection

foreach (int item in a)

Console.WriteLine(item);
 }

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
"System.Collections.Generic. List.Sort"
method in C#.NET

Sl. No

Method

11

void Sort()

This method sorts the collection in ascending order.

"System.Collections.Generic. List.Sort"
method - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithSortExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithSortExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithSortExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 50, 20, 100, 30, 500, 150, 300 };

//sort collection (in ascending order)

a.Sort();

//get values from list collection

foreach (int item in a)

Console.WriteLine(item);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
System.Collections.Generic. List - Sort
Descending - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ListWithSortDescendingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ListWithSortDescendingExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace ListWithSortDescendingExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 50, 20, 100, 30, 500, 150, 300 };

//sort collection (in descending order)

a.Sort();

a.Reverse();

//get values from list collection

foreach (int item in a)

{
 Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Collection Filter in .NET

Collection Filter

� To get elements based on the condition, write a foreach loop to iterate

through each element, check the condition and add the matching element
into another collection.
Collection Filter - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �CollectionFilterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CollectionFilterExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace CollectionFilterExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 50, 27, 105, 34, 55, 80, 100, 133 };

//create an empty new collection

List<int> b = new List<int>();

//read all the elements from "a" collection, check the condition, and
add the matching elements into a new collection called "b"

foreach (int item in a)

{
 if (item % 2 == 0)

b.Add(item);

//get values from the new collection

foreach (int item in b)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
LINQ in .NET

LINQ

� LINQ stands for "Language Integrated Query".

� It is a concept to retrieve conditional data from an array or collection & store
the matching elements in another collection.
� Syntax: from variable in collection where condition select
variable;
. The �from clause� represents the variable. Each value from the
collection will be loaded into the variable; and then the where
condition will be checked. If the condition is true, then the value will
be added to the result collection.
. The �in� clause represents the array / collection from which the data
has to be fetched.
. The �where� clause represents the condition to filter the data.
. The �select� clause represents the value that has to be added to the
result collection / array.
LINQ - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �LinqExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LinqExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

using System.Linq;

namespace LinqExample

class Program

static void Main()

//create list collection

List<int> a = new List<int> { 50, 27, 105, 34, 55, 80, 100, 133 };

//create an empty new collection

List<int> b = new List<int>();

//read all the elements from "a" collection, check the condition, and
add the matching elements into a new collection called "b" using LINQ
(Language Integrated Query)
 b = (from item in a where (item % 2 == 0) select item).ToList();

//get values from the new collection

foreach (int item in b)

Console.WriteLine(item);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Collection of Objects in .NET

Collection of Objects

� An object stores a set of data members.

� A "collection of objects" is a set of objects. Ex: Employees, Students etc.
Collection of Objects - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �CollectionOfObjectsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CollectionOfObjectsExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace CollectionOfObjectsExample

class Student

public int StudentID { get; set; }

public string StudentName { get; set; }

public int Marks { get; set; }

class Program

static void Main()

//create 4 reference variables for Student class

Student s1, s2, s3, s4;

//create 4 objects for Student class

s1 = new Student() { StudentID = 1, StudentName = "scott", Marks = 40 };

s2 = new Student() { StudentID = 2, StudentName = "allen", Marks = 70 };

s3 = new Student() { StudentID = 3, StudentName = "jones", Marks = 25 };

 s4 = new Student() { StudentID = 4, StudentName = "john", Marks = 50 };

//create a collection of "Student" type

List<Student> Students = new List<Student>();

//add objects to collection

Students.Add(s1);

Students.Add(s2);

Students.Add(s3);

Students.Add(s4);

//get objects from the collection

for (int i = 0; i < Students.Count; i++)

Console.Write(Students[i].StudentID);

Console.Write(", ");

Console.Write(Students[i].StudentName);

Console.Write(", ");

Console.WriteLine(Students[i].Marks);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Collection of Objects � Filter - Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CollectionOfObjectsFilterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CollectionOfObjectsFilterExample�. Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace CollectionOfObjectsFilterExample

class Student

public int StudentID { get; set; }

public string StudentName { get; set; }

public int Marks { get; set; }

class Program

static void Main()

//create 4 reference variables for Student class

Student s1, s2, s3, s4;

//create 4 objects for Student class

s1 = new Student() { StudentID = 1, StudentName = "scott", Marks = 40 };

s2 = new Student() { StudentID = 2, StudentName = "allen", Marks = 25 };

 s3 = new Student() { StudentID = 3, StudentName = "jones", Marks = 70 };

s4 = new Student() { StudentID = 4, StudentName = "john", Marks = 32 };

//create collection of Student type and initialize objects into the

collection with collection initializer

List<Student> Students = new List<Student>() { s1, s2, s3, s4 };

//create a new empty collection

List<Student> PassedStudents = new List<Student>();

//read all the objects from "Students" collection, check the condition,
and add matching objects into "PassedStudents" collection

for (int i = 0; i < Students.Count; i++)

Student s;

s = Students[i];

if (s.Marks >= 35)

PassedStudents.Add(s);

//get objects from the "PassedStudents" collection

for (int i = 0; i < PassedStudents.Count; i++)

Student s;

s = PassedStudents[i];

Console.Write(s.StudentID);

Console.Write(", ");

Console.Write(s.StudentName);

Console.Write(", ");

Console.WriteLine(s.Marks);

Console.ReadKey();
 }

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Collection of Objects � LINQ - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CollectionOfObjectsLinqExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CollectionOfObjectsLinqExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

using System.Linq;

namespace CollectionOfObjectsLinqExample

class Student

public int StudentID { get; set; }

public string StudentName { get; set; }

public int Marks { get; set; }

class Program

static void Main()

//create a collection of "Student" type and initialize 4 objects

List<Student> Students = new List<Student>()

new Student() { StudentID = 1, StudentName = "scott", Marks = 40 },

 new Student() { StudentID = 2, StudentName = "allen", Marks = 25 },

new Student() { StudentID = 3, StudentName = "jones", Marks = 70 },

new Student() { StudentID = 4, StudentName = "john", Marks = 32 }

};

//create a new empty collection

List<Student> PassedStudents = new List<Student>();

//read all the objects from "Students" collection, check the condition,
and add matching objects into a new collection using LINQ

//PassedStudents = (from s in Students where s.Marks >= 35 select

s).ToList();

PassedStudents = Students.Where(s => s.Marks >= 35).ToList();

//get objects from "PasssedStudents" collection

for (int i = 0; i < PassedStudents.Count; i++)

Student s;

s = PassedStudents[i];

Console.Write(s.StudentID);

Console.Write(", ");

Console.Write(s.StudentName);

Console.Write(", ");

Console.WriteLine(s.Marks);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "Dictionary" class in .NET

System.Collections.Generic.Dictionary

� "Dictionary" is a pre-defined class in "System.Collections.Generic"

namespace.
� Dictionary is used to store a set of pairs of key and values.
� Example:

Key

Value

Maths

60

Physics

70

Chemistry

80

� It is also generic class that receives two data types; one is for key; other one
is for value.
� We can get the value based on the key, rather than based on index.
The "Dictionary" class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DictionaryExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DictionaryExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace DictionaryExample

class Program

static void Main()

//create reference variable for dictionary collection

Dictionary<string, int> Marks;

//create object for dictionary collection

Marks = new Dictionary<string, int>();

//add items (keys and values)

Marks.Add("Maths", 86);

Marks.Add("Physics", 67);
 Marks.Add("Chemistry", 78);

//get value based on key

int m = Marks["Physics"];

Console.WriteLine(m);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "SortedList" class in .NET

System.Collections.Generic.SortedList

� "SortedList" is a pre-defined class in "System.Collections.Generic"

namespace.
� SortedList is also used to store a set of pairs of key and values.
� It is also generic class that receives two data types; one is for key, other one
is for value.
� It automatically sorts the data while adding elements itself. So that it will be
faster while retrieving the values.
� We can get the value based on the key, rather than based on index.
The "SortedList" class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �SortedListExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SortedListExample�.
� Click on OK.

Program.cs

using System;

using System.Collections.Generic;

namespace SortedListExample

class Program

static void Main()

//create reference variable for SortedList collection

SortedList<string, int> Marks;

//create object for SortedList collection

Marks = new SortedList<string, int>();

//add items (keys and values)

Marks.Add("Maths", 86);

Marks.Add("Physics", 67);

Marks.Add("Chemistry", 78);
 //get value based on the key

int m = Marks["Physics"];

Console.WriteLine(m);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "Hashtable" class in .NET

System.Collections.Hashtable

� "Hashtable" is a pre-defined class in "System.Collections" namespace.

� Hashtable is similar to Dictionary, but no need to specify the data types for
key and value; so that the key and value can be of any data type.
� It is not a generic class.
� We can get the value based on the key, rather than based on index.
The "Hashtable" class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �HashtableExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �HashtableExample�.
� Click on OK.

Program.cs

using System;

using System.Collections;

namespace HashtableExample

class Program

static void Main()

//create reference variable for Hashtable collection

Hashtable Marks;

//create object for Hashtable collection

Marks = new Hashtable();

//add items (keys and values)

Marks.Add("Maths", 86);

Marks.Add("Physics", 67);

Marks.Add("Chemistry", 78);

Marks.Add("StudentName", "scott");
 Marks.Add("IsRegistered", true);

//get value based on the key

int m = Convert.ToInt32(Marks["Physics"]);

Console.WriteLine(m);

//get value based on the key (another example)

bool b = Convert.ToBoolean(Marks["IsRegistered"]);

Console.WriteLine(b);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "ArrayList" class in .NET

System.Collections.ArrayList

� "ArrayList" is a pre-defined class in "System.Collections" namespace.

� It is similar to List, but no need to specify the data type for value; so that
the
value can be of any data type.
� It is also not a generic class.
The "ArrayList" class - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ArrayListExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ArrayListExample�.
� Click on OK.

Program.cs

using System;

using System.Collections;

namespace ArrayListExample

class Program

static void Main()

//create reference variable for ArrayList collection

ArrayList MyData;

//create object for ArrayList collection

MyData = new ArrayList();

//add items

MyData.Add(100);

MyData.Add(100.2398);

MyData.Add("hyderabad");

MyData.Add(true);

MyData.Add(DateTime.Now);
 //get items from the ArrayList collection

for (int i = 0; i < MyData.Count; i++)

Console.WriteLine(MyData[i]);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "typeof" operator in .NET

"typeof" operator:

� The "typeof" operator is used to check the data type of a value.

� Syntax: typeof (data type name)
The "typeof" operator - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �TypeofExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TypeofExample�.
� Click on OK.

Program.cs

using System;

using System.Collections;

namespace TypeofExample

class Program

static void Main()

//create reference variable for ArrayList collection

ArrayList MyData;

//create object for ArrayList collection

MyData = new ArrayList();

//add items

MyData.Add(100);

MyData.Add(150);
MyData.Add(100.2398);

MyData.Add("hyderabad");

MyData.Add(true);

MyData.Add(DateTime.Now);

//get items from the ArrayList collection

for (int i = 0; i < MyData.Count; i++)

if (MyData[i].GetType() == typeof(int))

int n = Convert.ToInt32(MyData[i]);

Console.WriteLine(n);

else if (MyData[i].GetType() == typeof(double))

double n = Convert.ToDouble(MyData[i]);

Console.WriteLine(n);

else if (MyData[i].GetType() == typeof(string))

string n = Convert.ToString(MyData[i]);

Console.WriteLine(n);

else if (MyData[i].GetType() == typeof(bool))

bool n = Convert.ToBoolean(MyData[i]);

Console.WriteLine(n);

else if (MyData[i].GetType() == typeof(DateTime))

{

DateTime n = Convert.ToDateTime(MyData[i]);

Console.WriteLine(n);

}
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.String" class in C#.NET (or)
String Handling in C#.NET

The �System.String� class

� In .NET, every string literal (a group of characters with double quotes) is

automatically treated as an object for "System.String" class.
� The �System.String� class provides a set of properties and methods to
manipulate strings.

Properties of �System.String� class:

1) int Length
. It returns the no. of characters in the string.

Methods of �System.String� class:

1) string ToUpper()
. It returns the string in upper case.

2) string ToLower()
. It returns the string in lower case.

3) char [int index]

. It returns the character at specified index.

4) string Substring(int startIndex)

. It returns the part of the string, starting from specified index,
up to end of the string.
5) string Substring(int startIndex, int length)
. It returns the part of the string, starting from specified index,
the specified no. of characters.
6) string Remove(int index)
. It removes the part of the string, starting from specified index,
up to end of the string, and returns the remaining string.

7) string Remove(int index, int length)

. It removes the part of the string, starting from specified index,
up to specified length, and returns the remaining string.

8) string Insert(int index, string value)

. It inserts the given string value in the main string at the
specified index and returns the result string.

9) bool Equals(string value)

. It compares the main string and string value, whether those
are equal or not. It returns true if the both are equal. It returns
false if both are not equal.

10) bool Equals(string value,

StringComparison.OrdinalIgnoreCase)
. Same as �Equals� method, but it ignores the case (upper case /
lower case).

11) bool StartsWith(string value)

. It returns true if the given value exists at the beginning of
string. It returns false if the give value exists at the beginning
of string.
12) bool EndsWith(string value)
. It returns true if the given value exists at the ending of string.
It returns false if the give value not exists at the ending of
string.

13) bool Contains(string value)

. It returns true if the given value exists in the string. It returns
false if the given value exists in the string.

14) int IndexOf(string value)

. It searches and returns the index of first character of given
value in the string. It returns -1 if is not found.

15) int IndexOf(string value, int startIndex)

. It is same as previous method, but searching starts from
specified startIndex.

16) int LastIndexOf(string value, int startIndex)

. It is same as IndexOf() method, but searching starts from end
of the string. (searching will be done from right-to-left).

17) string Replace(string oldValue, string newValue)

. It replaces each occurrence of oldValue with newValue and
returns it.
18) char[ ] ToCharArray()
. It converts and returns the string as a character array.

19) string[ ] Split(char separator)

. It splits the string into small strings on each occurrence of
given separator and returns all small strings as a string array.
20) string Trim()
. It returns the un-necessary spaces at the beginning and ending
of the string; and it returns the final string.

21) static string Format(string format, object arg0, object

arg1, �)
. It substitutes place holders with the arguments, and returns
the final string. It is a static method.

Note: No string method modifies the existing string object. It creates a

new string object, stores the result string in it and returns the same
string object.
�System.String.Length� - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LengthExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LengthExample�.
� Click on OK.

Program.cs

using System;

namespace LengthExample

class Program

static void Main()

//create a string

string s = "Hyderabad";

//get length (no. of characters in the string)

int len = s.Length;

//display length (no. of characters in the string)

Console.WriteLine(len); //Output: 9

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.ToUpper� - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ToUpperExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ToUpperExample�.
� Click on OK.

Program.cs

using System;

namespace ToUpperExample

class Program

static void Main()

//create a string

string s = "Hyderabad";

//convert the string into upper case

string s2 = s.ToUpper();

//display

Console.WriteLine(s); //Output: Hyderabad

Console.WriteLine(s2); //Output: HYDERABAD

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.ToLower� - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ToLowerExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ToLowerExample�.
� Click on OK.

Program.cs

using System;

namespace ToLowerExample

class Program

static void Main()

//create a string

string s = "HYDERABAD";

//convert into lower case

string s2 = s.ToLower();

//display

Console.WriteLine(s); //Output: HYDERABAD

Console.WriteLine(s2); //Output: hyderabad

 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.GetChar� - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �GetCharExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �GetCharExample�.
� Click on OK.

Program.cs

using System;

namespace GetCharExample

class Program

static void Main()

//create a string

string s = "Hyderabad";

//get the character at index no. "4".

char ch = s[4];

//display

Console.WriteLine(ch); //Output: r

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Substring� � Example 1

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SubstringExample1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SubstringExample1�.
� Click on OK.

Program.cs

using System;

namespace SubstringExample1

class Program

static void Main()

//create a string

string s = "Hyderabad";

//get sub string (from 4th character - till end of the string)

string s2 = s.Substring(4);

//display

Console.WriteLine(s2); //Output: rabad

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Substring� � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SubstringExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SubstringExample2�.
� Click on OK.

Program.cs

using System;

namespace SubstringExample2

class Program

static void Main()

//create a string

string s = "hyderabad";

//get sub string (from 4th character - only 2 characters length)

string s2 = s.Substring(4, 2);

//display

Console.WriteLine(s2); //Output: ra

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Remove� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �RemoveExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �RemoveExample�.
� Click on OK.

Program.cs

using System;

namespace RemoveExample

class Program

static void Main()

//create string & integer

string s = "Hyderabad";

int ind = 4;

//remove part of the string, starting from index "4" - till the end of
string & return the remaining part of the string.

string s2 = s.Remove(ind);

//display

Console.WriteLine(s2); //Output: Hyde

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Remove� � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �RemoveExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �RemoveExample2�.
� Click on OK.

Program.cs

using System;

namespace RemoveExample2

class Program

static void Main()

//create string & integers

string s = "Hyderabad";

int ind = 4;

int len = 3;

//remove part of the string, starting from index "4" - upto "3"
characters length & get the remaining part of the string

string s2 = s.Remove(ind, len);

//display

Console.WriteLine(s2); //Output: Hydead

 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Insert� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �InsertExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InsertExample�.
� Click on OK.

Program.cs

using System;

namespace InsertExample

class Program

static void Main()

//create strings & integer

string s = "Hyderabad";

string s2 = "abc";

int ind = 4;

//insert "abc" in "Hyderabad" at index no. 4

string s3 = s.Insert(ind, s2);

//display

Console.WriteLine(s3); //Output: Hydeabcrabad

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Equals� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EqualsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EqualsExample�.
� Click on OK.

Program.cs

using System;

namespace EqualsExample

class Program

static void Main()

//create strings

string s1 = "Hyderabad";

string s2 = "Hyderabad";

//check whether s2 is equal to s1 or not

bool b = s1.Equals(s2);

//display

Console.WriteLine(b); //Output: True

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.StringComparison.
OrdinalIgnoreCase� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IgnoreCaseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IgnoreCaseExample�.
� Click on OK.

Program.cs

using System;

namespace IgnoreCaseExample

class Program

static void Main()

//create strings

string s1 = "Hyderabad";

string s2 = "hyderabad";

//check whether s2 is equal to s1 or not, ignoring case

bool b = s1.Equals(s2, StringComparison.OrdinalIgnoreCase);

//display

Console.WriteLine(b); //Output: True

 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.StartsWith� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StartsWithExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StartsWithExample�.
� Click on OK.

Program.cs

using System;

namespace StartsWithExample

class Program

static void Main()

//create strings

string s = "hyderabad";

string s2 = "hyd";

//check whether "hyderabad" starting with "hyd" or not

bool b = s.StartsWith(s2);

Console.WriteLine(b); //Output: True

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.EndsWith� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EndsWithExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EndsWithExample�.
� Click on OK.

Program.cs

using System;

namespace EndsWithExample

class Program

static void Main()

//create strings

string s = "hyderabad";

string s2 = "bad";

//check whether "hyderabad" ending with "bad" or not

bool b = s.EndsWith(s2);

Console.WriteLine(b); //Output: True

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Contains� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ContainsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ContainsExample�.
� Click on OK.

Program.cs

using System;

namespace ContainsExample

class Program

static void Main()

//create strings

string s = "Hyderabad";

string s2 = "dera";

//check whether "Hyderabad" contains "dera" or not

bool b = s.Contains(s2);

//display

Console.WriteLine(b); //Output: True

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.IndexOf� � Example 1

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IndexOfExample1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IndexOfExample1�.
� Click on OK.

Program.cs

using System;

namespace IndexOfExample1

class Program

static void Main()

//create strings

string s = "Hyderabad";

string s2 = "dera";

//get the index of "dera" in "Hyderabad"

int ind = s.IndexOf(s2);

//display

Console.WriteLine(ind); //2

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.IndexOf� � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IndexOfExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IndexOfExample2�.
� Click on OK.

Program.cs

using System;

namespace IndexOfExample2

class Program

static void Main()

//create strings

string s = "hyderabad";

string s2 = "a";

//get the index of "a" in "hyderabad" - first occurrence

int ind1 = s.IndexOf(s2);

Console.WriteLine(ind1); //5

//get the index of "a" in "hyderabad" - second occurrence

int ind2 = s.IndexOf(s2, ind1+1);

Console.WriteLine(ind2); //7
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.IndexOf� � Example 3

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IndexOfExample3�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IndexOfExample3�.
� Click on OK.

Program.cs

using System;

namespace IndexOfExample3

class Program

static void Main()

//create strings

string s = "Hyderabad";

string s2 = "xyz";

//get the index of "xyz" in "Hyderabad". As it is not found, it returns -1

int ind = s.IndexOf(s2);

//display

Console.WriteLine(ind); //Output: -1

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.LastIndexOf� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LastIndexOfExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LastIndexOfExample�.
� Click on OK.

Program.cs

using System;

namespace LastIndexOfExample

class Program

static void Main()

//create strings

string s = "Hyderabad";

string s2 = "a";

//get the last index of "a" in "Hyderabad" - Last occurrence

int ind = s.LastIndexOf(s2);

//display

Console.WriteLine(ind); //7
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Replace� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ReplaceExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ReplaceExample�.
� Click on OK.

Program.cs

using System;

namespace ReplaceExample

class Program

static void Main()

//create strings

string s = "Apple Smart Phones";

string s2 = "Apple";

string s3 = "Samsung";

//replace "Apple" with "Samsung"

string s4 = s.Replace(s2, s3);

Console.WriteLine(s4); //Output: Samsung Smart Phones

 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.ToCharArray� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ToCharArrayExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ToCharArrayExample�.
� Click on OK.

Program.cs

using System;

namespace ToCharArrayExample

class Program

static void Main()

//create string

string s = "hyderabad";

//convert "string" into "character array"

char[ ] ch = s.ToCharArray();

//read each character from the "character array" using for loop

for (int i = 0; i < ch.Length; i++)

Console.WriteLine(ch[i]);

}
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Converting CharArray to String - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CharArrayToStringExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CharArrayToStringExample�.
� Click on OK.

Program.cs

using System;

namespace CharArrayToStringExample

class Program

static void Main()

//create character array

char[ ] ch = new char[9] { 'H', 'y', 'd', 'e', 'r', 'a', 'b', 'a', 'd' };

//convert character array to string

string s = new String(ch);

//display string

Console.WriteLine(s); //Output: Hyderabad

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Split� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SplitExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SplitExample�.
� Click on OK.

Program.cs

using System;

namespace SplitExample

class Program

static void Main()

//create string and character

string s = "Hyderabad is one of the cities in India";

char ch = ' ';

//convert the "string" into "string array" at each occurrence of " "
(space)

string[ ] s2 = s.Split(ch);

//read and display each element from the string array

for (int i = 0; i < s2.Length; i++)

 {

Console.WriteLine(s2[i]);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Trim� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �TrimExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TrimExample�.
� Click on OK.

Program.cs

using System;

namespace TrimExample

class Program

static void Main()

//create string

string s = " Hyderabad ";

//get no. of characters

int len1 = s.Length;

Console.WriteLine(s); //Output: " Hyderabad "

Console.WriteLine(len1); //Output: 16

Console.WriteLine();

//trim the string (remove extra spaces at "most left side" and "most
right side")
 string s2 = s.Trim();

int len2 = s2.Length;

Console.WriteLine(s2); //Output: "Hyderabad"

Console.WriteLine(len2); //Output: 9

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Format� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �FormatExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FormatExample�.
� Click on OK.

Program.cs

using System;

namespace FormatExample

class Program

static void Main()

//create strings

string s1 = "scott";

string s2 = "allen";

string original = "{0} and {1} are now friends";

//Substitute "scott" in {0} place and "allen" in {1} place.

string final = string.Format(original, s1, s2);

Console.WriteLine(final); //Output: scott and allen are now friends.

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.String.Reverse� � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ReverseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ReverseExample�.
� Click on OK.

Program.cs

using System;

namespace ReverseExample

class Program

static void Main()

//create strings

string s = "hyderabad";

string s2 = "";

//read each character using for loop and append it to a new string

for (int i = s.Length - 1; i >= 0; i--)

s2 = s2 + s[i];

}
 Console.WriteLine(s2); //dabaredyh

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � WordsCount - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �WordsCountExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �WordsCountExample�.
� Click on OK.

Program.cs

using System;

namespace WordsCountExample

class Program

static void Main()

//create a string

string s = "She sells sea shells on the sea shore";

//create counter variable

int c = 0;

//read each character and check it whether the character is " " (space)
or not. If it is space, increment the counter variable

for (int i = 0; i < s.Length; i++)

{
 if (s[i] == ' ')

c++;

//increment the counter variable

if (s.Length >=1)

c++;

Console.WriteLine(c); //Output: 8

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � Character Occurrence Count -
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CharacterOccurrenceCountExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CharacterOccurrenceCountExample�.
� Click on OK.

Program.cs

using System;

namespace CharacterOccurrenceCountExample

class Program

static void Main()

//create a string

string s = "She sells sea shells on the sea shore";

//create a character

char ch = 's';

//create a counter variable

int c = 0;
 //read each character and check whether the character matches or
not. If matches, increment the counter variable

for (int i = 0; i < s.Length; i++)

if (s[i] == ch)

c++;

Console.WriteLine(c); //Output: 7

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � Alphabetic Count - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �AlphabetsCountExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AlphabetsCountExample�.
� Click on OK.

Program.cs

using System;

namespace AlphabetsCountExample

class Program

static void Main()

//create a string

string s = "She sells sea shells on the sea shore";

//create a counter variable

int c = 0;

//read each character and check whether it is alphabet or not, using

ASCII code

for (int i = 0; i < s.Length; i++)

if ( (s[i] >=65 && s[i] <=90) || (s[i] >=97 && s[i] <=122) )
 c++;

Console.WriteLine(c); //Output: 30

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � Word Occurrence Count - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �WordOccurrenceCountExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �WordOccurrenceCountExample�.
� Click on OK.

Program.cs

using System;

namespace WordOccurrenceCountExample

class Program

static void Main()

//create strings

string s = "She sells sea shells on the sea shore";

string s2 = "sea";

//create a counter variable

int c = 0;

//read each character

for (int i = 0; i < s.Length; i++)

{
 //check whether the chracter matches with the first character of
"s2".

if (s[i] == s2[0] && (i + s2.Length) <= s.Length)

bool flag = true;

//check for remaining characters of "s2".

for (int j = i, k = 0; k < s2.Length; j++, k++)

if (s[j] != s2[k])

flag = false;

//if all the chracters are matched, increment the counter variable

if (flag == true)

c++;

Console.WriteLine(c); //Output: 2

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � Title Case - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �TitleCaseExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TitleCaseExample�.
� Click on OK.

Program.cs

using System;

namespace TitleCaseExample

class Program

static void Main()

//create strings

string s = "she sells sea shells on the sea shore";

string s2 = "";

char ch = ' ';

//split the string into "string array" at each occurrence of space.

string[ ] words = s.Split(ch);

//converting into "Title Case" (Every word starts with capital letter).

for (int i = 0; i < words.Length; i++)

{
 s2 += words[i][0].ToString().ToUpper() +
words[i].Substring(1).ToLower() + " ";

//remove unnecessary spaces

s2 = s2.Trim();

Console.WriteLine(s2); //Output: She Sells Sea Shells On The Sea

Shore

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � Currency into words - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CurrencyIntoWordsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CurrencyIntoWordsExample�.
� Click on OK.

Program.cs

using System;

using System.Text;

namespace CurrencyIntoWordsExample

class Program

static void Main()

//actual number that is to be converted into currency

int number = 1234;

//create string

string result;

//check whether the number is zero

if (number == 0)

{
 result = "Zero";

goto end;

//create integer array

int[ ] num = new int[4];

int first = 0;

int u, h, t;

//create stringbuilder

StringBuilder sb = new StringBuilder();

//check whether the number is negetive

if (number < 0)

sb.Append("Minus ");

number = -number;

//create string arrays

string[ ] words0 = {"" ,"One ", "Two ", "Three ", "Four ", "Five " ,"Six ",
"Seven ", "Eight ", "Nine "};

string[ ] words1 = {"Ten ", "Eleven ", "Twelve ", "Thirteen ", "Fourteen ",
"Fifteen ","Sixteen ","Seventeen ","Eighteen ", "Nineteen "};

string[ ] words2 = {"Twenty ", "Thirty ", "Forty ", "Fifty ", "Sixty ",
"Seventy ","Eighty ", "Ninety "};

string[ ] words3 = { "Thousand ", "Lakh ", "Crore " };

num[0] = number % 1000; // units

num[1] = number / 1000;

num[2] = number / 100000;

num[1] = num[1] - 100 * num[2]; // thousands

num[3] = number / 10000000; // crores

num[2] = num[2] - 100 * num[3]; // lakhs

 for (int i = 3; i > 0; i--)

if (num[i] != 0)

first = i;

break;

for (int i = first; i >= 0; i--)

if (num[i] == 0) continue;

u = num[i] % 10; // ones

t = num[i] / 10;

h = num[i] / 100; // hundreds

t = t - 10 * h; // tens

if (h > 0) sb.Append(words0[h] + "Hundred ");

if (u > 0 || t > 0)

if ((h > 0 || i == 0) && (number.ToString().Length > 3))

sb.Append("and ");

if (t == 0)

sb.Append(words0[u]);

else if (t == 1)

sb.Append(words1[u]);

else

sb.Append(words2[t - 2] + words0[u]);

if (i != 0) sb.Append(words3[i - 1]);
}

result = sb.ToString().TrimEnd();

end:

Console.WriteLine(number);
 Console.WriteLine(result);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
String � Multiple Concatenations - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MultipleConcatenationsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultipleConcatenationsExample�.
� Click on OK.

Program.cs

using System;

namespace MultipleConcatenationsExample

class Program

static void Main()

//create strings

string s1, s2, s3, s4, result;

s1 = "Hello "; //string object 1

s2 = "how "; //string object 2

s3 = "are "; //string object 3

s4 = "you"; //string object 4

//concatenations

result = s1;

result = result + s2; //string object 5

 result = result + s3; //string object 6

result = result + s4; //string object 7

Console.WriteLine(result); //Output: Hello how are you

Console.ReadKey();

//Total no. of objects created in the program = 7

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Text.StringBuilder" class in
C#.NET

System.Text.StringBuilder

� �StringBuilder� is a pre-defined class in �System.Text� namespace.

� This class�s object represents an appendable string.
� The string builder can be appendable any no. of times, without creating a
separate object.
� String concatenation always creates a new object for �System.String� class;
but string builder allows the value to be appended any no. of times. So
string builder saves memory when compared with string concatenation, in
case of many appendings.
Steps for development of StringBuilder:

� Import the namespace:

. using System.Text;

� Create a reference variable:

. StringBuilder sb;

� Create an object for StringBuilder class:

. sb = new StringBuilder();

� Append string:
. sb.Append(string value);

� Convert the stringbuilder to string:

. sb.ToString();
The "System.Text.StringBuilder" class -
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �StringBuilderExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StringBuilderExample�.
� Click on OK.

Program.cs

using System;

using System.Text;

namespace StringBuilderExample

class Program

static void Main()

//create strings

string s1, s2, s3, s4;

s1 = "Hello "; //string object 1

s2 = "how "; //string object 2

s3 = "are "; //string object 3

s4 = "you"; //string object 4

//create reference variable

StringBuilder result;
 //create object for StringBuilder class

result = new StringBuilder();

//append strings to the stringbuilder

result.Append(s1);

result.Append(s2);

result.Append(s3);

result.Append(s4);

Console.WriteLine(result.ToString()); //Output: Hello how are you

Console.ReadKey();

//Total no. of objects created in the program = 4

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime" structure in C#.NET
(or) Date & Time Handling in C#.NET

The �System.DateTime� structure

� .NET provides a pre-defined structure called �DateTime�, to store and

manipulate date & time.
� �DateTime� is a structure; �System� is a namespace.
� The �DateTime� structure provides several properties and methods to
perform manipulations on date and time.

Properties of �System.DateTime� structure:

1) DateTime Now
. It returns the current system date and time.

2) int Day
. It returns the current day. (1 to 31).

3) int Month
. It returns the current month. (1 to 12).

4) int Year
. It returns the current year. (1 to 12).

5) int Hour
. It returns the current hour.
6) int Minute
. It returns the current minute.

7) int Second
. It returns the current second.
8) int MilliSecond
. It returns the current milli second.

9) string DayOfWeek.ToString()
. It returns the day name of the week.

10) int DayOfYear

. It returns the current day�s index in the current year.

Methods of �System.DateTime� structure:

11) string ToShortDateString()

. It returns the date in the following format: M/d/yyyy

12) string ToLongDateString()

. It returns the date in the following format: dddd, MMMM dd, yyyy

13) string ToShortTimeString()

. It returns the time in the following format: h:m tt
14) string ToLongTimeString()
. It returns the time in the following format: h:mm:ss tt

15) string ToString(�format�)

. It returns the date / time in the desired format.

16) TimeSpan Subtract(DateTime dt2)

. It subtracts the main date with given dt2, and returns the difference
dates in the form of TimeSpan.

17) DateTime AddDays(int n)

. It adds the �n� no. of days to the main date and returns the result date.
The "System.DateTime" � First Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �DateTimeFirstExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DateTimeFirstExample�.
� Click on OK.

Program.cs

using System;

namespace DateTimeFirstExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set value

d = Convert.ToDateTime("2/10/2016 5:30 PM");

//get value

Console.WriteLine(d);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime.Now" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �NowExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NowExample�.
� Click on OK.

Program.cs

using System;

namespace NowExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get value

Console.WriteLine(d);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime" � Inner Values �
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �InnerValuesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InnerValuesExample�.
� Click on OK.

Program.cs

using System;

namespace InnerValuesExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get individual values

int dy = d.Day;

int m = d.Month;

int y = d.Year;
 int h = d.Hour;

int mi = d.Minute;

int s = d.Second;

int ms = d.Millisecond;

//display values

Console.WriteLine("Day: " + dy);

Console.WriteLine("Month: " + m);

Console.WriteLine("Year: " + y);

Console.WriteLine();

Console.WriteLine("Hour: " + h);

Console.WriteLine("Minute:" + mi);

Console.WriteLine("Second: " + s);

Console.WriteLine();

Console.WriteLine("Milli Second: " + ms);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime.DayOfWeek" �
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �DayOfWeekExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DayOfWeekExample�.
� Click on OK.

Program.cs

using System;

namespace DayOfWeekExample

class Program

static void Main()

//create variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get name of the day of week

string str = d.DayOfWeek.ToString();

Console.WriteLine(str);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime.DayOfYear" �
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DayOfYearExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DayOfYearExample�.
� Click on OK.

Program.cs

using System;

namespace DayOfYearExample

class Program

static void Main()

//create variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get no. of the day in the current year (1 to 365)

int n = d.DayOfYear;

Console.WriteLine(n);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime. ToShortDateString"
� Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �ShortDateExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ShortDateExample�.
� Click on OK.

Program.cs

using System;

namespace ShortDateExample

class Program

static void Main()

//create variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get short date

string str = d.ToShortDateString();

Console.WriteLine(str);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime. ToLongDateString" �
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LongDateExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LongDateExample�.
� Click on OK.

Program.cs

using System;

namespace LongDateExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get long date

string str = d.ToLongDateString();

Console.WriteLine(str);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime. ToShortTimeString"
� Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ShortTimeExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ShortTimeExample�.
� Click on OK.

Program.cs

using System;

namespace ShortTimeExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get short time

string str = d.ToShortTimeString();

Console.WriteLine(str);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime. ToLongTimeString" �
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LongTimeExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LongTimeExample�.
� Click on OK.

Program.cs

using System;

namespace LongTimeExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get long time

string str = d.ToLongTimeString();

Console.WriteLine(str);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime" � Custom Formats �
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CustomFormatsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CustomFormatsExample�.
� Click on OK.

Program.cs

using System;

namespace CustomFormatsExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//get custom formats

string str1 = d.ToString("d/M/yyyy");

string str2 = d.ToString("yyyy/M/d");

string str3 = d.ToString("h:m:s");

 //display values

Console.WriteLine("d/M/yyyy: " + str1);

Console.WriteLine("yyyy/M/d: " + str2);

Console.WriteLine("h:m:s: " + str3);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime.Subtract" � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SubstractExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SubtractExample�.
� Click on OK.

Program.cs

using System;

namespace SubtractExample

class Program

static void Main()

//create variables of DateTime data type

DateTime dt1, dt2;

dt1 = DateTime.Now;

dt2 = Convert.ToDateTime("7/8/2011"); ;

//subtract dt2 from dt1 (get the no. of days between 7/8 /2011 till
date)

TimeSpan ts;

ts = dt1.Subtract(dt2);

//display the no. of days difference between dt1 and dt2 (dt1 - dt2)
 string msg = ts.TotalDays + " days";

Console.WriteLine(msg);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.DateTime.AddDays" � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �AddDaysExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AddDaysExample�.
� Click on OK.

Program.cs

using System;

namespace AddDaysExample

class Program

static void Main()

//create a variable of DateTime data type

DateTime d;

//set system date and time into the variable

d = DateTime.Now;

//add 10 days

DateTime temp = d.AddDays(10);

Console.WriteLine(temp);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math" class in C#.NET

The �System.Math� class

� .NET provides a pre-defined class called �Math�, to store perform

mathematical manipulations.
� �Math� is a class; �System� is a namespace.
� �Math� is a static class; so all of its members are �static members�.

Methods of �System.Math� class:

1) double Abs(double value)

. It returns the absolute value (positive value) of given number.

2) double Floor(double value)

. It returns the number without decimal part.

3) double Ceiling(double value)

. It returns the next number without decimal part.

4) double Round(double value)

. It returns the current number without decimal part, if the first
digit of the decimal part is less than 5.
. It returns the next number without decimal part, if the first digit
of the decimal part is greater than or equal to 5.

5) double Max(double n1, double n2)

. It returns the big number.
6) double Min(double n1, double n2)
. It returns the small number.
7) double Pow(double n1, double n2)
. It returns n1 power n2.

8) double Sqrt(double n)
. It returns the square root of �n�.
The "System.Math.Abs" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AbsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AbsExample�.
� Click on OK.

Program.cs

using System;

namespace AbsExample

class Program

static void Main()

double n = -100;

double result;

//convert the negetive value into positive value

result = Math.Abs(n);

Console.WriteLine(n);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Floor" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �FloorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FloorExample�.
� Click on OK.

Program.cs

using System;

namespace FloorExample

class Program

static void Main()

double n = 100.3492;

double result;

//get the floor value (without decimal part)

result = Math.Floor(n);

Console.WriteLine(n);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Ceiling" � Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �CeilingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �CeilingExample�.
� Click on OK.

Program.cs

using System;

namespace CeilingExample

class Program

static void Main()

double n = 100.3492;

double result;

//get the next integer value

result = Math.Ceiling(n);

Console.WriteLine(n);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Round" � Example 1

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �RoundExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �RoundExample�.
� Click on OK.

Program.cs

using System;

namespace RoundExample

class Program

static void Main()

double n = 100.3492;

double result;

//get the next number if the first digit in decimal part is greater than
or equal to "5"; get the previous number if the first digit in decimal part is
less than "5".

result = Math.Round(n);

Console.WriteLine(n);

Console.WriteLine(result);
 Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Round" � Example 2

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �RoundExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �RoundExample2�.
� Click on OK.

Program.cs

using System;

namespace RoundExample2

class Program

static void Main()

double n = 100.6492;

double result1, result2;

result1 = Math.Round(n);

result2 = Math.Round(n, 2);

Console.WriteLine(result1);

Console.WriteLine(result2);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Max" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MaxExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MaxExample�.
� Click on OK.

Program.cs

using System;

namespace MaxExample

class Program

static void Main()

double n1 = 100, n2 = 200;

double result;

//get the big value among n1 and n2

result = Math.Max(n1, n2);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Min" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MinExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MinExample�.
� Click on OK.

Program.cs

using System;

namespace MinExample

class Program

static void Main()

double n1 = 100, n2 = 200;

double result;

//get the smaller value among n1 and n2

result = Math.Min(n1, n2);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Pow" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �PowExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �PowExample�.
� Click on OK.

Program.cs

using System;

namespace PowExample

class Program

static void Main()

double n1 = 10, n2 = 3;

double result;

//get the result of "10" power "3"

result = Math.Pow(n1, n2);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The "System.Math.Sqrt" �Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SqrtExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SqrtExample�.
� Click on OK.

Program.cs

using System;

namespace SqrtExample

class Program

static void Main()

double n = 10;

double result;

//get square root of 10

result = Math.Sqrt(n);

Console.WriteLine(result);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
�System.Diagnostics.Process� class in
C#.NET

System.Diagnostics.Process

� �Process� is a pre-defined class in �System.Diagnostics� namespace.

� This class�s object represents an exe file (executable file).
� �Process� class is used to run an exe file.
� We can pass parameters to the exe file.

Syntax: System.Diagnostics.Process.Start("exe file path",

parameters);
�System.Diagnostics.Process� class -
Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ProcessExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ProcessExample�.
� Click on OK.

Program.cs

using System;

using System.Diagnostics;

namespace ProcessExample

class Program

static void Main()

//call "System.Diagnostics.Process.Start" method to run calculator

Process.Start(@"C:\windows\system32\calc.exe");

//show message

Console.WriteLine("Calculator opened");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Command Line Arguments in C#.NET

Command Line Arguments

� It is used to receive one or more argument values from command prompt

(command line).
� All the command line arguments will be received by the Main method as a
string array.
� This technique is used in most of the windows applications such as Notepad,
MS Office Word, VLC Media Player etc.
� Syntax: filename.exe value1 value2 �
Command Line Arguments - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �App1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �App1�.
� Click on OK.

Program.cs

using System;

namespace App1

class Program

static void Main(string[ ] args)

if (args.Length >= 2)

Console.WriteLine(args[0]);

Console.WriteLine(args[1]);

Console.ReadKey();

}
Running the project

� Press Windows + R to open �Run� window.

� Type the following command.

C:\CSharp\App1\App1\bin\Debug\App1.exe 10 20

� Click on OK.

Output
Nullable Data Types in C#.NET

Nullable Data Types

� Null means �nothing� (or) �blank�.

� Data types are two types:
1) Value-type data types (or) Structures (or) Non-nullable data types
. The �structure variable� will be stored in �Stack� in RAM.
. Null values are not supported.

2) Reference-type data types (or) Classes (or) Nullable data types

. The �objects� will be stored in �Heap� in RAM.
. Null values are supported.

Syntax to convert non-nullable data type to nullable data type:

� Structurename? variable = null;

[or]

� Nullable<Structurename> variable = null;

Nullable Data Types - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �NullableDataTypesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �NullableDataTypesExample�.
� Click on OK.

Program.cs

using System;

namespace NullableDataTypesExample

class Program

static void Main()

//create a nullable variable

int? n;

//set "null" value into nullable variable

n = null;

//get the value of nullable variable

Console.WriteLine("n value is: " + n);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Exception Handling in C#.NET

Exception Handling

� Exception means �run time error�.

� When a statement can�t be executed due to some reason, system treat it as
a run time error (exception).
� When a runtime error found, automatically CLR raises the exception.
� Exceptions raise based on different factors like programmer�s mistake,
system problem, database connection or SQL statement execution problem
etc.
� When exception is raised, the programs gets terminated un-expectedly (or)
abruptly. It is inconvenience to the user. So the programmer has to use
�exception handling� concept to avoid un-expected closing of the
application.
� Exception handling is used to catch the run time errors (exceptions) and
display the error message on the same page, instead of closing the
application un-expectedly.
� Syntax:

try

Code here

catch (Exception ex)

Code here

finally

Code here

� �Try� block: Executes normally.

� �Catch� block: Executes only when the exception is raised in try block. It
receives the exception details as �ex� object.
o Message: Exception message
o Stack Trace: Method called sequence

� �Finally� block�: Executes after completion of try block or catch block.

Finally block is optional.
Exception Handling - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ExceptionHandlingExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ExceptionHandlingExample�.
� Click on OK.

Program.cs

using System;

namespace ExceptionHandlingExample

class Program

static void Main()

try

Console.Write("Enter first number: ");

int a = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter second number: ");

int b = Convert.ToInt32(Console.ReadLine());

int c = a / b;

Console.WriteLine("Quotient is " + c);

 }

catch (Exception ex)

Console.WriteLine(ex.Message);

finally

Console.WriteLine("Finished");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Destructor in C#.NET

Destructor

� Destructor is a special method of the class, which will be automatically

called before deleting each object of the class.
� By using �destructors�, C#.NET allows the programmer to execute any code,
just before deleting an object.
� Destructor�s name should be same as current class name.
� Destructor can�t have arguments and return value.
� A class can have only one destructor.
� Destructor can�t be overloaded.
� Syntax of destructor:

~classname()

}
Destructor - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DestructorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DestructorExample�.
� Click on OK.

Program.cs

using System;

namespace DestructorExample

class Class1

//constructor

public Class1()

Console.WriteLine("Constructor");

//Ex: opening the db connection

//destructor

~Class1()

Console.WriteLine("Destructor");

//Ex: closing the db connection

}
 }

class Program

static void Main()

Class1 c1 = new Class1(); //constructor will be called here

//lot of code

//db work is over

Console.ReadKey();

} //destructor will be called here

Running the Project

� Go to �Debug� menu and click on �Start without Debugging�.

Output
The "System.IDisposable" interface

System.IDisposable

� �System.IDisposable� is a pre-defined interface, which contains only one

abstract method called �Dispose�. The �Dispose� method will be called
automatically, when �using� statement is used while creating object. In the
�Dipose� method, you can perform any cleaning process such as closing
database connections or closing files etc.
� The benefit of using �Dispose� method instead of �destructor� is: the
�Dispose� method will be called automatically as soon as �using� statement
ends; then the cleaning process will be performed through �Dispose�
method; so that we release the resources such as database connections and
file connections; no need to wait until the end of the application.

Syntax of inhering from �System.IDisposable� interface:

class classname : System.IDisposable

public void Dispose()

referencevariable = null;

Syntax of inhering from �System.IDisposable� interface:

using (classname referencevariable = new classname())

}
The "System.IDisposable" interface -
Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IDisposeExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IDisposeExample�. Click on OK.

Program.cs

using System;

namespace IDisposeExample

class Class1 : System.IDisposable

public Class1()

Console.WriteLine("object created");

//db connection opened

public void method1()

Console.WriteLine("method1");

public void Dispose()

Console.WriteLine("disposed");

//db connection closed

~Class1()

{
 //destructor

Console.WriteLine("destructor");

class Program

static void Main()

using (Class1 c1 = new Class1())

c1.method1();

} //Dispose

Console.ReadKey();

} //Destructor

Running the Project

� Go to �Debug� menu and click on �Start without Debugging�.

Output
Garbage Collection in C#.NET

Garbage Collection

� Garbage collection is a process of deleting unreferenced variables or objects

from memory.
� Garbage collection will be performed automatically; but it will be performed
at the end of main method only.
� To perform garbage collection immediately, use System.GC.Collect()
method.
� Syntax: System.GC.Collect();
Garbage Collection - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �GarbageCollectionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �GarbageCollectionExample�.
� Click on OK.

Program.cs

using System;

namespace GarbageCollectionExample

class Class1

~Class1()

Console.WriteLine("Destructor");

class Program

static void Main()

//create two objects

Class1 c1 = new Class1();

Class1 c2 = new Class1();

 c1 = null;

//delete all the objects

GC.Collect();

Console.WriteLine("Garbage collection done.");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start without Debugging�.

Output
Delegates in C#.NET

Delegates

� Delegate is a reference variable that contains reference of one or more

methods that have same signature.
o Single Cast Delegates: Contains reference of only one method.
o Multi Cast Delegates: Contains reference of multiple methods.

� We can call the target method using delegate.

� We don�t use delegates individually; we use delegates only in events.
� The �delegate type� is used to specify signature of the target method.

Steps for development of delegates:

� Create a target method:

accessmodifier returntype methodname(arguments)

� Create delegate type (in the namespace):

public delegate returntype delegatetypename(arguments);

� Create a delegate (in the class or method);

delegatetypename delegatename;

� Store the address of target method in the delegate:

delegatename = methodname;

� Call the method indirectly using delegate:

delegatename(value1, value2, ..);

Single Cast Delegates - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SingleCastDelegatesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SingleCastDelegatesExample�. Click on OK.

Program.cs

using System;

namespace SingleCastDelegatesExample

class Class1

//create target method

public void Add(int a, int b)

int c = a + b;

Console.WriteLine("Sum is " + c);

//create a delegate type

public delegate void MyDelegateType(int a, int b);

class Program

static void Main()

 {

//create a delegate

MyDelegateType d;

//create object

Class1 c1 = new Class1();

//store the address of Add method into delegate

d = c1.Add;

//call the Add method using delegate

d(10, 20);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start without Debugging�.

Output
Multi Cast Delegates - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MultiCastDelegatesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultiCastDelegatesExample�.
� Click on OK.

Program.cs

using System;

namespace MultiCastDelegatesExample

class Class1

//create target method 1

public void Add(int a, int b)

int c = a + b;

Console.WriteLine("Sum is " + c);

//create target method 2

public void Subtract(int a, int b)

int c = a - b;

Console.WriteLine("Difference is " + c);

}
 }

//create a delegate type

public delegate void MyDelegateType(int a, int b);

class Program

static void Main()

//create a delegate

MyDelegateType d;

//create object

Class1 c1 = new Class1();

//store the address of Add method into delegate

d = c1.Add;

//store the address of Subtract method also into the delegate

d += c1.Subtract;

//call the Add and Subtract methods using delegate

d(10, 3);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start without Debugging�.

Output
Events in C#.NET

Events

� Events are used to implement �publisher � subscriber� model.

� �Publisher� is a class that contains an event and also raises the event.
� �Subscriber� is a class that subscribes to the event of publisher class. That
means subscriber class provides an event handler that can be attached to
the event.
� When the event is raised in the publisher class, the event handler method
will be executed.
� An event can be subscribed with multiple methods also.
� In real time, publisher class will be developed by one programmer and
subscriber class will be developed by other programmer.

Steps for development of events:

� Create a delegate type (in the namespace):

public delegate returntype delegatetypename(argument1,

argument2, �)

� Create publisher class:

class publisherclassname

}
� Create an event in the publisher class:

public event delegatypename eventname;

� Raise the event in the publisher class:

eventname (value1, value2, �)

� Create subscriber class:

class subscriberclassname

{
}

� Create the event handler method in subscriber class:

public returntype methodname (arguments)

� Attach the event handler method to the event:

eventname += methodname ;
Events - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EventsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EventsExample�. Click on OK.

Program.cs

using System;

namespace EventsExample

public delegate void mydelegatetypename(string username);

class publisherclass

public event mydelegatetypename myevent;

public void raiseevent(string username)

myevent(username); //raise event

class subscriberclass

public void subscribedmethod(string username)

Console.WriteLine("Hello to " + username);

}
 public void connect()

publisherclass pc = new publisherclass();

pc.myevent += subscribedmethod;

pc.raiseevent("Scott");

pc.raiseevent("Allen");

class Program

static void Main()

subscriberclass sc = new subscriberclass();

sc.connect();

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Anonymous Methods

Anonymous methods

� Anonymous methods are used to quickly create a method inside another

method.
� Anonymous methods are useful while handling the events.
� Anonymous methods can�t be a member of the class.
� Anonymous methods will have no name.
� Anonymous method�s address should be stored in a delegate (or) event,
through the delegate or event only we can call it.

Syntax of anonymous method:

delegate / event = delegate(argument1, argument2, �)

Code here

}
Anonymous Methods - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AnonymousMethodsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AnonymousMethodsExample�.
� Click on OK.

Program.cs

using System;

namespace AnonymousMethodsExample

class publisherclass

public event mydelegatetype myevent;

public int x = 0, y = 0;

public void increment()

x += 5;

y += 5;

myevent(x, y);

class subscriberclass

{
 public void dowork()

publisherclass pc = new publisherclass();

pc.myevent += delegate(int a, int b)

int c = a + b;

Console.WriteLine("Sum is " + c);

};

pc.increment();

delegate void mydelegatetype(int a, int b);

class Program

static void Main()

subscriberclass sc = new subscriberclass();

sc.dowork();

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Lambda Expressions

Lambda Expressions

� Lambda Expressions are used to quickly create a method inside another

method.
� Lambda Expressions are useful while handling the events.
� Lambda Expressions can�t be a member of the class.
� Lambda Expressions will have no name.
� Lambda Expressions�s address should be stored in a delegate (or) event,
through the delegate or event only we can call it.

Syntax of Lambda Expressions:

delegate / event = (argument1, argument2, �) =>

Code here

}
Lambda Expressions - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LambdaExpressionsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LambdaExpressionsExample�.
� Click on OK.

Program.cs

using System;

namespace LambdaExpressionsExample

class publisherclass

public event mydelegatetype myevent;

public int x = 0, y = 0;

public void increment()

x += 5;

y += 5;

myevent(x, y);

class subscriberclass

public void dowork()

publisherclass pc = new publisherclass();

pc.myevent += (a, b) =>

 {

int c = a + b;

Console.WriteLine("Sum is " + c);

};

pc.increment();

delegate void mydelegatetype(int a, int b);

class Program

static void Main()

subscriberclass sc = new subscriberclass();

sc.dowork();

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Inline Lambda Expressions

Inline Lambda Expressions

� Inline Lambda Expressions are similar to lambda expressions, but can be

used only for the methods that receives one of more arguments and return
a value.
� Inline lambda expressions can contain only just a single calculation; can�t
contain any other additional code.
� Inline lambda expressions can receive or more arguments; must return a
value.

Syntax of Inline Lambda Expressions:

delegate / event = (argument1, argument2, �) =>

Calculation here

)
Inline Lambda Expressions - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InlineLambdaExpressionsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InlineLambdaExpressionsExample�.
� Click on OK.

Program.cs

using System;

namespace InlineLambdaExample

class publisherclass

public event mydelegatetype myevent;

public int x = 0, y = 0;

public void increment()

x += 5;

y += 5;

int result = myevent(x, y);

Console.WriteLine("Sum is " + result);

class subscriberclass

public void dowork()

 {

publisherclass pc = new publisherclass();

pc.myevent += (a, b) => ( a + b );

pc.increment();

delegate int mydelegatetype(int a, int b);

class Program

static void Main()

subscriberclass sc = new subscriberclass();

sc.dowork();

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Inner Classes in C#.NET

Inner Classes

� Class inside another class is called as �inner class�.

� The class that encloses inner class, is called as �outer class�.
� Use �inner class�, if you want to specify that the class is a part of the outer
class logically.

Syntax to create inner class

class outerclassname

public class innerclassname

Syntax to access the inner class

outerclassname . innerclassname
Inner Classes - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InnerClassesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InnerClassesExample�.
� Click on OK.

Program.cs

using System;

namespace InnerClassesExample

class Class1

public class Class2

public void mymethod()

Console.WriteLine("mymethod");

class Program

static void Main()

{
 Class1.Class2 c2 = new Class1.Class2();

c2.mymethod();

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Indexer in C#.NET

Indexer

� Indexer makes it easy to access a member array through the reference

variable of a class.
� Indexer is a property with name �this�.
� Indexer overloading is possible. That means we can create multiple indexers
in the same class, with different arguments.
� Mostly indexers are used in pre-defined classes; it�s rare to use indexers in
user-defined classes in real time.

Syntax to create indexer:

class classname

public datatype this[string variablename]

get

return value ;

set

Datamember = value ;

Syntax to access the indexer: Referencevariable["string value"]

Indexer - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �IndexerExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �IndexerExample�.
� Click on OK.

Program.cs

using System;

namespace IndexerExample

class Class1

//creating an array

public string[] cities = new string[] { "Hyderabad", "Chennai",

"Bangalore" };

public long[] population = new long[] { 9000, 5000, 10000 };

//indexer

public long this[string city]

get

int n = Array.IndexOf(cities, city);

return population[n];

}
 }

class Program

static void Main()

Class1 c1 = new Class1();

long p = c1["Chennai"];

Console.WriteLine(p);

//Console.Write(c1.population[Array.IndexOf(c1.cities, "Chennai")]);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Assemblies in C#.NET

Assembly

� In .NET, an �Assembly� is a file that contains �compiled source code (in MSIL
language) of the .net program�.
� Assemblies can�t be run directly based on the operating system; can only by
run by CLR (Common Language Runtime). CLR reads MSIL code from
assembly and convert the same into native machine language automatically,
while .net program exection.
� Assemblies are two types:
1. Executable assemblies
2. Library assemblies

Executable Assemblies

� �Executable assemblies� are �EXE files� that can run directly (based on CLR).
� When you compile the following types of applications, Visual Studio
automatically generates (creates) an �Executable Assembly�:
o Console Application
o Windows Forms Application
o Windows Service

� Drawback: The code of executable assemblies (projects) can�t be called in

another assemblies (projects).

Library Assemblies

� �Library Assemblies� are �DLL files� that can�t run directly. The library
assemblies are always �supporting files� to �Executable Assembly�.
Executable assemblies dynamically call the library assemblies at run time.
� When you compile the following types of applications, Visual Studio
automatically generates (creates) an �Library Assembly�:
o Class Library
o Windows Forms Control Library
� An �executable assembly� can call any no. of library assemblies.
� A �library assembly� can be called by any no. of executable assemblies.

Types of Library Assemblies

� Library assemblies are divided into two types, based on where the library
assembly is placed.
� Library assemblies are two types:
1. Private Assemblies
2. Shared Assemblies

Private Assemblies

� Private assemblies (dll files) should be placed in each �application folder�.

� Private assemblies are faster in execution but there is memory wastage, if
multiple applications are consuming the same private assembly and are
running on same system.

Shared Assemblies

� Shared assemblies are located in GAC (Global Assembly Cache) folder and
can be accessed by the applications that are running on the same system.
� Shared assemblies save memory, because there is no need of duplicate
copies of dll file in every app�s folder.
� Shared assemblies are a bit slower than private assemblies.

GAC

� GAC (Global Assembly Cache) is a special folder in .NET Framework, which

contains all the shared assemblies (shared dll files).
� The shared dll files that are present at GAC folder can be accessible from
any application running in the same system.
� GAC Folder: C:\Windows\Microsoft.NET\assembly\GAC_MSIL
� Advantage of GAC folder: Avoid the �DLL hell�.
� DLL hell: When we install a new version of an application, the dll files of old
version of the application will be overwritten with latest version�s dll files.
GAC folder solves this problem with unique identification of dll files.

SNK

� An assembly must have �snk� (Strong Name Key) to be placed in GAC folder.
� SNK (Strong Name Key) file is contains �unique code�, which is useful for
�unique identification� of dll files that are placed in GAC folder.
� SNK file can be created in visual studio through the �project properties� �
�Signing� option.

Class Library

� �Class Library� is a special type of project in Visual Studio.

� Class Library is a collection of re-usable classes.
� When the class library project is compiled, a �library assembly� (DLL file) will
be genereated.
Class Libraries & Private Assemblies -
Example

Creating Class Library

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Class Library�.
� Type the project name as �ClassLibrary1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ClassLibrary1�.
� Click on OK.

Class1.cs

using System;

namespace ClassLibrary1

public class Class1

public bool CheckEmail(string Email)

bool b;

if (Email.Contains(" ") == false && Email.IndexOf("@") > 0)

b = true;

else

b = false;

return b;
 }

Compiling the project

� Go to �Build� menu and click on �Build Solution�.

� Note: You can�t run the class library directly.
� Path of dll file:
C:\CSharp\ClassLibrary1\ClassLibrary1\bin\Debug\ClassLibrary1.dll
Creating the client project (Console Application):

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConsoleApplication1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConsoleApplication1�.
� Click on OK.

Add reference

� Open solution explorer.

� Right click on the project name (ConsoleApplication1) and click on �Add� �
�Reference�.
� Click on �Browse�.
� Select the dll file
(C:\CSharp\ClassLibrary1\ClassLibrary1\bin\Debug\ClassLibrary1.dll).
� Click on �Add� � �OK�.
� Then it shows the �ClassLibrary1� in the �References� list in the solution
explorer.
Program.cs

using System;

using ClassLibrary1;

namespace ConsoleApplication1

class Program

static void Main()

Class1 c1 = new Class1();

string s = "sample@gmail.com";

bool result = c1.CheckEmail(s);

if (result == true)

Console.WriteLine(s);

Console.WriteLine("Valid email address");

else

Console.WriteLine(s);

Console.WriteLine("Invalid email address");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Shared Assemblies - Example

Creating Class Library

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Class Library�.
� Type the project name as �ClassLibrary2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ClassLibrary2�.
� Click on OK.

Class1.cs

using System;

namespace ClassLibrary2

public class Class1

public bool CheckEmail(string Email)

bool b;

if (Email.Contains(" ") == false && Email.IndexOf("@") > 0)

b = true;

else

b = false;

return b;
 }

Creating �snk� file:

� To create snk file, open solution explorer; right click on the project name
�ClassLibrary2� and click on �Properties�.
� Click on �Signing�. Check the checkbox �Sign the assembly�.
� Click on the dropdown list and click on �New�.
� Type the file name as �demo�. Uncheck the checkbox �protect my key file
with a password�. Click on OK.
� Close the properties window.
Compiling the project

� Go to �Build� menu and click on �Build Solution�.

� Note: You can�t run the class library directly.

Path of dll file:

C:\CSharp\ClassLibrary2\ClassLibrary2\bin\Debug\ClassLibrary2.dll
Uploading the dll file into GAC

� Go to �Start� � �All Programs� � �Visual Studio 2015� � Right click on

�Developer Command Prompt for VS 2015� and click on �Run as
administrator�. Click on �Yes�.
� Type the following command in the console window:

gacutil �i
"C:\CSharp\ClassLibrary2\ClassLibrary2\bin\Debug\ClassLibrary2.dll"

� Press Enter.
� It shows the following message:

Assembly successfully added to the cache.

Creating the client project (Console Application):

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConsoleApplication2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConsoleApplication2�.
� Click on OK.

Add reference

� Open solution explorer.

� Right click on the project name (ConsoleApplication2) and click on �Add� �
�Reference�.
� Click on �Browse�.
� Select the dll file
(C:\CSharp\ClassLibrary2\ClassLibrary2\bin\Debug\ClassLibrary2.dll).
� Click on �Add� � �OK�.
� Then it shows the �ClassLibrary2� in the �References� list in the solution
explorer.
� Note: You can notice that the �ClassLibrary2.dll� file is not present in
�C:\CSharp\ConsoleApplication2\ConsoleApplication2\bin\Debug� folder.
Even it is present, the �ConsoleApplication2.exe� file works without
�ClassLibrary2.dll� file present in the same folder, because it will be
accessed from the GAC folder.
Program.cs

using System;

using ClassLibrary2;

namespace ConsoleApplication2

class Program

static void Main()

Class1 c1 = new Class1();

string s = "sample@gmail.com";

bool result = c1.CheckEmail(s);

if (result == true)

Console.WriteLine(s);

Console.WriteLine("Valid email address");

else

Console.WriteLine(s);

Console.WriteLine("Invalid email address");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Access Modifiers in C#.NET

Access Modifiers

� Access Modifiers are also called as �Access Specifiers�, which are used to
specify the access privileges of a member of a class.
� Access Modifiers can be applicable to all types of members (such as data
member, method, constructor, property etc.) that tell which classes can
access the member and which can�t.
� Access Modifiers are used to create security for the member of a class.

� List of access modifiers in c#.net:

1. private (default)
2. protected
3. internal
4. protected internal
5. public

1. private: The private members are accessible �only within the same
class�. These are not accessible in any other classes. �Private� is the
default access modifier in c#.net. That means, if you don�t specify any
access modifier, by default, �private� will be applied.

2. protected: The protected members are accessible �within the same

class� and also within the �child classes at same project� and �child
classes at other projects�. These are not accessible in any other classes.
Note: The other projects must add the reference of current project.

3. internal: The internal members are accessible �anywhere within the

same project�. These are not accessible in any classes at other projects.

4. protected internal: �Protected internal� is a combination of �protected�

and �internal�. The protected internal members are accessible �anywhere
within the project� and also accessible �within the child classes at other
projects�. These are not accessible in other classes at other projects.
Note: The other projects must add the reference of current project.

5. public: The public members are accessible �everywhere�.

C:\Users\Harsha\OneDrive\C#.NET\72. Access Modifiers\Access Modifiers.png

Access Modifiers - Example

Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �AccessModifiersExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �AccessModifiersExample�. Click on OK.

Program.cs

namespace AccessModifiersExample

//same class

class Class1

private int a; //private member

protected int b; //protected member

internal int c; //internal member

protected internal int d; //protected internal member

public int e; //public member

public void Method1()

a = 10; //private member is accessible in the same class

b = 20; //protected member is accessible in the same class

c = 30; //internal member is accessible in the same class

d = 40; //protected internal member is accessible in the same class

e = 50; //public member is accessible in the same class

}
//child class in the same project
 class Class2: Class1

public void Method2()

b = 20; //protected member is accessible in the child class at same

project

c = 30; //internal member is accessible in the child class at same

project

d = 40; //protected internal member is accessible in the child class at

same project

e = 50; //public member is accessible in the child class at same project

//other class in the same project

class Class3

public void Method3()

Class1 c1 = new Class1();

c1.c = 30; //internal member is accessible in the other class at same

project

c1.d = 40; //protected internal member is accessible in the other class

at same project

c1.e = 50; //public member is accessible in the other class at same

project

//other class in the same project

class Program

{
static void Main()

Class1 c1 = new Class1();

 c1.c = 30; //internal member is accessible in the other class at same
project

c1.d = 40; //protected internal member is accessible in the other class

at same project

c1.e = 50; //public member is accessible in the other class at same

project

System.Console.WriteLine("Done");

System.Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Access Modifiers for classes

Access Modifiers for Classes

� Access Modifiers can be used for classes also, to specify where the class is
accessible.
� The following access modifiers can be used for classes:
� List of access modifiers for classes in c#.net:
1. internal (default)
2. public
3. private

1. internal: The internal classes can be accessible within the same project
only. They are not accessible in other projects. �Internal� is the default
access modifier for the classes.

2. public: The public classes can be accessible anywhere (within the same
project and also in other projects too).

3. private: Only inner classes can be �private classes�. The �private inner
classes� can be accessible within the same outer classes only. They are
not accessible in other classes.
Documentation Comments

Documentation Comments

� Documentation comments are used to provide description for the methods

and its arguments, which will be appear while calling the method (while
typing the code in visual studio).

Syntax for method description:

/// <summary>Method description here</summary>

Syntax for parameter description:

/// <param name="parameter name">Parameter description

here</param>
Documentation Comments - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DocumentationCommentsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DocumentationCommentsExample�.
� Click on OK.

Program.cs

using System;

namespace DocumentationCommentsExample

class Class1

/// <summary>Adds two numbers</summary>

/// <param name="firstNumber">First number for adding</param>

/// <param name="secondNumber">Second number for

adding</param>

public void Add(int firstNumber, int secondNumber)

//code here

class Program

static void Main()

{
 Class1 c1 = new Class1();

c1.Add(10, 20);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

While typing the code in visual studio, it shows the description as

tooltip.
Extension Methods in C#.NET

Extension Methods

� Extension methods are methods that are indirectly injected into a compiled
class, without modifying its source code.
� Assume, there is a re-usable class in the class library and its reference is
added in the client project.
� From the class library, you can add a new method to the re-usable class,
without modifying the source code of the re-usable class.
� That method is called as �extension method�.
� Extension method should be a static method; it should be inside a static
class.
� It should be public method.
� It should have atleas one argument of the target class type with �this�
keyword. That argument represents �this� keyword in the extension
method. �This� keyword represents the current object, based on which the
method is called.
� The extension method can have maximum any no. of arguments, but
minimum is one.
� The extension method can have any return type.

Syntax of extension method (in the class library):

public static class classname

public static returntype methodname(this classname

argumentname)

Code here

Syntax of call the extension method (in the client app):

referencevariablename.methodname (arguments);
Extension Methods - Example

Creating Class Library

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Class Library�.
� Type the project name as �ClassLibrary1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ClassLibrary1�.
� Click on OK.

Class1.cs

using System;

namespace ClassLibrary1

public class Class1

public double getsquare(double n)

double sq = n * n;

return sq;

}
Compiling the project

� Go to �Build� menu and click on �Build Solution�.

� Note: You can�t run the class library directly.
� Path of dll file:
C:\CSharp\ClassLibrary1\ClassLibrary1\bin\Debug\ClassLibrary1.dll

Creating the client project (Console Application):

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ConsoleApplication1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ConsoleApplication1�.
� Click on OK.
Add reference

� Open solution explorer.

� Right click on the project name (ConsoleApplication1) and click on �Add� �
�Reference�.
� Click on �Browse�.
� Select the dll file
(C:\CSharp\ClassLibrary1\ClassLibrary1\bin\Debug\ClassLibrary1.dll).
� Click on �Add� � �OK�.
� Then it shows the �ClassLibrary1� in the �References� list in the solution
explorer.

Program.cs

using System;

using ClassLibrary1;

namespace ConsoleApplication1

static class Class2

public static double getcube(this Class1 c1, double n)

double cb = n * n * n;

return cb;

class Program

static void Main()

Class1 c1 = new Class1();

int a = 10;
 double result1 = c1.getsquare(a);

Console.WriteLine("Square is " + result1);

double result2 = c1.getcube(a);

Console.WriteLine("Cube is " + result2);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
C#.NET � Console - System.IO
Namespace
Introduction to "System.IO" namespace

System.IO namespace

� The �System.IO� namespace provides a set of classes to manipulate files and

folders in the hard disk.
� List of important classes in System.IO namespace:
1. System.IO.FileInfo
2. System.IO.DirectoryInfo
3. System.IO.File
4. System.IO.Directory
5. System.IO.FileStream
6. System.IO.StreamWriter
7. System.IO.StreamReader
The �System.IO.FileInfo� class

System.IO.FileInfo class

� The �FileInfo� is a class in �System.IO� namespace.

� The �FileInfo� class�s object represents a file in the harddisk.
� The �FileInfo� class is used to manipulate a file in the harddisk.

Steps for development of �FileInfo� class:

� Import the namespace:

o using System.IO;

� Create a reference variable:

o FileInfo referencevariable;

� Create an object:
o referencevariable = new FileInfo( �file path� );

� Set properties:
o referencevariable.property = value ;

� Call method:
o referencevariable.methodname ();
Properties of �FileInfo� class:

Sl.
No

Property

Description

DirectoryName

Represents the current file�s location�s full path.

Syntax: referencevariable.DirectoryName

Name

Represents only name of the file with extension (without

path).

Syntax: referencevariable.Name

Extension

Represents file extension of current file.

Syntax: referencevariable.Extension

FullName

Represents full path of the current file.

Syntax: referencevariable.FullName

Exists

Represents whether the current file exists or not. It returns a

Boolean value.

True: The file exists

False: The file not exists

Syntax: referencevariable.Exists

Length
Represents file size (no. of bytes).

Syntax: referencevariable.Length

CreationTime

Represents the date and time of file creation.

Syntax: referencevariable.CreationTime

LastAccessTime

Represents the date and time of file access.

Syntax: referencevariable.LastAccessTime

LastWriteTime

Represents the date and time of file last modification.

Syntax: referencevariable.LastWriteTime

10

Attributes

Represents the attributes of the current file.

Syntax: referencevariable.Attributes

11

IsReadOnly

Represents whether the current file is readonly or not.

Syntax: referencevariable.IsReadOnly
Constructors of �FileInfo� class:

Sl.
No

Constructor

Description

FileInfo()

Initializes the file path.

Syntax: new FileInfo(string FilePath)

Methods of �FileInfo� class:

Sl.
No

Method

Description

CopyTo()

Copies the current file into the specified destination path.

It is equal to �copy and paste�.

Syntax: referencevariable.CopyTo(string DestinationFilePath)

Delete()

Deletes the current file.

Syntax: referencevariable.Delete()

MoveTo()

Movies the current file into the specified destination path.

It is equal to �cut and paste�.

Syntax: referencevariable.MoveTo(string DestinationFilePath)

The �System.IO.FileInfo� class - Example

Creating Project

� Create the following folders and files:

o C:\CSharp
. Sample.pdf

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �FileInfoExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FileInfoExample�.
� Click on OK.

Program.cs

//Note: Create "C:\CSharp\sample.txt"

using System;

using System.IO;

namespace namespace1

class Program

static void Main()

FileInfo f;
f = new FileInfo(@"c:\CSharp\sample.txt");

Console.WriteLine("Exists: " + f.Exists);

 if (f.Exists)

Console.WriteLine("Full name: " + f.FullName);

Console.WriteLine("Name: " + f.Name);

Console.WriteLine("Directory name: " + f.DirectoryName);

Console.WriteLine("Extension: " + f.Extension);

Console.WriteLine("Creation date and time: " + f.CreationTime);

Console.WriteLine("Modification date and time: " +

f.LastWriteTime);

Console.WriteLine("Access date and time: " + f.LastAccessTime);

Console.WriteLine("Length: " + f.Length + " bytes");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

It shows the file details as above.

The �System.IO.DirectoryInfo� class

System.IO.DirectoryInfo class

� The �DirectoryInfo� is a class in �System.IO� namespace.

� The �DirectoryInfo� class�s object represents a folder (directory) in the
harddisk.
� The �DirectoryInfo� class is used to manipulate a folder (directory) in the
harddisk.

Steps for development of �DirectoryInfo� class:

� Import the namespace:

o using System.IO;

� Create a reference variable:

o DirectoryInfo referencevariable;

� Create an object:
o referencevariable = new DirectoryInfo( �folder path� );

� Set properties:
o referencevariable.property = value ;

� Call method:
o referencevariable.methodname ();
Properties of �DirectoryInfo� class:

Sl.
No

Property

Description

Parent.FullName

Represents the current folder�s parent folder�s full path.

Syntax: referencevariable.Parent.FullName

Name

Represents only name of the folder (without parent

folder�s path).

Syntax: referencevariable.Name

FullName

Represents full path of the current folder.

Syntax: referencevariable.FullName

Root.FullName

Represents full path of the root folder of the current

folder.

Syntax: referencevariable.Root.FullName

Exists

Represents whether the current folder exists or not. It

returns a Boolean value.

True: The folder exists

False: The folder not exists

Syntax: referencevariable.Exists

6
CreationTime

Represents the date and time of folder creation.

Syntax: referencevariable.CreationTime

LastAccessTime

Represents the date and time of folder access.

Syntax: referencevariable.LastAccessTime

LastWriteTime

Represents the date and time of folder last modification.

Syntax: referencevariable.LastWriteTime

Attributes

Represents the attributes of the current folder.

Syntax: referencevariable.Attributes
Constructors of �DirectoryInfo� class:

Sl.
No

Constructor

Description

DirectoryInfo()

Initializes the folder path.

Syntax: new DirectoryInfo(string FolderPath)

Methods of �DirectoryInfo� class:

Sl.
No

Method

Description

Delete()

Deletes the current folder, if it is empty.

If the current folder is not empty, it throws an

exception automatically.

Syntax: referencevariable.Delete()

Delete(true)

Deletes the current folder, including all of its files and

sub folders.

Syntax: referencevariable.Delete(true)

Warning: This action is permanent. It is impossible to

undo this action. Check the folder path before
running the program.

MoveTo()
Movies the current folder into the specified
destination path.

It is equal to �cut and paste�.

Note: The destination folder path should be in the

same drive. Ex: C: drive

Syntax: referencevariable.MoveTo(string
DestinationFolderPath)

CreateSubdirectory()

Creates a new folder with specified name.

Syntax: referencevariable.CreateSubdirectory(string
newfoldername)
5

GetFiles()

Returns the list of files of the current folder, as an

array of FileInfo[].

Syntax: referencevariable.GetFiles()

GetDirectories()

Returns the list of sub directories of the current

folder, as an array of DirectoryInfo[].

Syntax: referencevariable.GetDirectories()
The �System.IO.DirectoryInfo� class -
Example

Creating Project

� Create the following folders and files:

o C:\CSharp
. sample
� firstfolder (folder)
� secondfolder (folder)
� thirdfolder (folder)
� New Text Document.txt
� New Microsoft Word Document.docx

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DirectoryInfoExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DirectoryInfoExample�.
� Click on OK.
Program.cs

using System;

using System.IO;

namespace namespace1

class Program

static void Main()

DirectoryInfo d;

d = new DirectoryInfo(@"c:\CSharp\myfolder");

Console.WriteLine("Exists: " + d.Exists);

if (d.Exists)

Console.WriteLine("Full name: " + d.FullName);

Console.WriteLine("Name: " + d.Name);

Console.WriteLine("Directory name: " + d.Parent);

Console.WriteLine("Creation date and time: " + d.CreationTime);

Console.WriteLine("Modification date and time: " +

d.LastWriteTime);

Console.WriteLine("Access date and time: " + d.LastAccessTime);

Console.WriteLine("\nFiles:");

FileInfo[] files = d.GetFiles();

for (int i = 0; i < files.Length; i++)

Console.WriteLine(files[i].FullName);

}
Console.WriteLine("\nSub directories:");

DirectoryInfo[] directories = d.GetDirectories();

for (int i = 0; i < directories.Length; i++)

 {

Console.WriteLine(directories[i].FullName);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

It shows the folder details as above.

The �System.IO.Directory� class

System.IO.Directory class

� The �Directory� is a class in �System.IO� namespace.

� The �Directory� class is a static class, which provides a set of static methods
to manipulate folders.

Steps for development of �Directory� class:

� Import the namespace:

o using System.IO;

� Call any static method:

o Directory.method ();

Methods of �Directory� class:

Sl.
No

Method

Description

Exists()

Checks whether the folder exists or not.

True: The folder exists.

False: The folder not exists

Syntax: Directory.Exists(string FolderPath)

CreateDirectory()
Create the specified folder and returns corresponding
DirectoryInfo�s object.

Syntax: Directory.CreateDirectory(string FolderPath)

3

Delete()

Deletes the specified folder permanently, including all of its

sub folders and files in it.

Syntax: Directory.Delete(string FolderPath, true)

Warning: This action is permanent. It is impossible to undo

this action. Check the folder path before running the
program.

Move()

Moves the specified source folder into the specified

destination location.

Rule: Both source and destination location should be in the

same drive. Ex: C: drive

Syntax: Directory.Move(string SourceFolderPath, string

DestinationFolderPath)
The �System.IO.Directory� class - Example

Creating Project

� Create the following folders:

o C:\CSharp
. Sample (folder)

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DirectoryExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DirectoryExample�.
� Click on OK.

Program.cs

using System;

using System.IO;

namespace DirectoryExample

class Program

static void Main()

if (Directory.Exists(@"c:\folder1") == true)

Directory.Delete(@"C:\folder1", true);
}

if (Directory.Exists(@"c:\folder2") == true)
 {

Directory.Delete(@"C:\folder2", true);

Directory.CreateDirectory(@"C:\folder1");

Console.WriteLine("folder1 created");

Console.WriteLine("folder1 exists: " + Directory.Exists(@"C:\folder1"));

//Output: True

Directory.Delete(@"C:\folder1");

Console.WriteLine("folder1 deleted");

Console.WriteLine("folder1 exists: " + Directory.Exists(@"C:\folder1"));

//Output: False

Directory.CreateDirectory(@"C:\folder1");

Console.WriteLine("folder1 created");

Directory.Move(@"C:\folder1", @"C:\folder2");

Console.WriteLine("folder1 moved as folder2");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The �System.IO.File� class

System.IO.File class

� The �File� is a class in �System.IO� namespace.

� The �File� class is a static class, which provides a set of static methods to
manipulate files.

Steps for development of �File� class:

� Import the namespace:

o using System.IO;

� Call any static method:

o File.method ();

Methods of �File� class:

Sl.
No

Method

Description

Exists()

Checks whether the file exists or not.

True: The file exists.

False: The file not exists

Syntax: File.Exists(string FilePath)

Create()
Create the specified file and returns corresponding FileStream�s
object.

Syntax: File.Create(string FilePath)

3

Delete()

Deletes the specified file permanently.

Syntax: File.Delete(string FilePath)

Warning: This action is permanent. It is impossible to undo this

action. Check the file path before running the program.

Move()

Moves the specified source file into the specified destination

location.

Syntax: File.Move(string SourceFilePath, string

DestinationFilePath)

Copy()

Copies the specified source file into the specified destination

location.

Syntax: File.Copy(string SourceFilePath, string

DestinationFilePath)
The �System.IO.File� class - Example

Creating Project

� Create the following folders and files:

o C:\CSharp

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �FileExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FileExample�. Click on OK.

Program.cs

using System;

using System.IO;

namespace FileExample

class Program

static void Main()

if (Directory.Exists(@"c:\folder1") == true)

Directory.Delete(@"c:\folder1", true);

Directory.CreateDirectory(@"c:\folder1");

Console.WriteLine("Folder created");

File.Create(@"c:\folder1\file1.txt").Close();
Console.WriteLine("File created");
 File.Copy(@"c:\folder1\file1.txt", @"c:\folder1\file2.txt");

Console.WriteLine("File created");

File.Move(@"c:\folder1\file2.txt", @"c:\folder1\file3.txt");

Console.WriteLine("File moved");

Console.WriteLine("File exists: " + File.Exists(@"c:\folder1\file3.txt"));

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
The �System.IO.FileStream� class

System.IO.FileStream class

� The �FileStream� is a class in �System.IO� namespace.

� The �FileStream� class is used to write data to a file (or) read data from an
existing file in byte[ ] format.
� But in fact, it is difficult to deal with byte[ ]. That�s why, often we use
StreamWriter or StreamReader to perform file reading or writing
operations.
� �FileStream� is useful while working with �StreamWriter� or
�StreamReader�.
� �FileStream� is a child class of a parent class called �Stream�.
� �FileStream� supports two modes majorly:
o �Create� mode: Used to create a new file and write data into the new
file.
o �Read� mode: Used to read data from an existing file.
Steps for development of �FileStream� class (Create
mode):

� Import the namespace:

o using System.IO;

� Create a reference variable:

o FileStream referencevariable;

� Create an object:
o referencevariable = new FileStream( �file path�, FileMode.Create,
FileAccess.Write );

Steps for development of �FileStream� class (Open mode):

� Import the namespace:

o using System.IO;

� Create a reference variable:

o FileStream referencevariable;

� Create an object:
o referencevariable = new FileStream( �file path�, FileMode.Open,
FileAccess.Read );
The �System.IO.StreamWriter� class

System.IO.StreamWriter class

� The �StreamWriter� is a class in �System.IO� namespace.

� The �StreamWriter� class is used to write data to a new / existing file in text
format.
� �StreamWriter� is usually used in combination with �FileStream�.

Steps for development of �StreamWriter� class:

� Import the namespace:

o using System.IO;

� Create a reference variable:

o StreamWriter referencevariable;

� Create an object:
o referencevariable = new StreamWriter( file stream object here );

� Write data to file:

o referencevariable.Write (string content);

� Close the file:

o referencevariable.Close ();
The �System.IO.StreamWriter� class -
Example

Creating Project

� Create the following folder:

o C:\CSharp

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �StreamWriterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StreamWriterExample�. Click on OK.

Program.cs

//city.txt

using System;

using System.IO;

namespace namespace1

class Program

static void Main()

//delete the file, if it already exists

FileInfo f = new FileInfo(@"c:\CSharp\file1.txt");

if (f.Exists == true)

f.Delete();

//create the file

FileStream fs = new FileStream(@"c:\CSharp\file1.txt",

FileMode.Create, FileAccess.Write);
 //write data to the file

StreamWriter sw = new StreamWriter(fs);

sw.WriteLine("Hai");

sw.WriteLine("Hello");

sw.WriteLine("How are you");

//close the file

sw.Close();

Console.WriteLine("Written");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

The file will be created at �C:\Sharp\sample.txt�.

The �System.IO.StreamReader� class

System.IO.StreamReader class

� The �StreamReader� is a class in �System.IO� namespace.

� The �StreamReader� class is used to read data from an existing file in text
format.
� �StreamReader� is usually used in combination with �FileStream�.

Steps for development of �StreamReader� class:

� Import the namespace:

o using System.IO;

� Create a reference variable:

o StreamReader referencevariable;

� Create an object:
o referencevariable = new StreamReader( file stream object here );

� Read complete content of the file:

o string variablename = referencevariable.ReadToEnd( );

� Close the file:

o referencevariable.Close( );
The �System.IO.StreamReader� class -
Example

Creating Project

� Create the following folder:

o C:\CSharp

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�.
� Select �Visual C#�. Select �Console Application�.
� Type the project name as �StreamReaderExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �StreamReaderExample�. Click on OK.

Program.cs

//city.txt

using System;

using System.IO;

namespace namespace1

class Program

static void Main()

//check the file exists or not

FileInfo f = new FileInfo(@"c:\CSharp\file1.txt");

if (f.Exists == true)

//open the file

FileStream fs = new FileStream(@"c:\CSharp\file1.txt",

FileMode.Open, FileAccess.Read);

//read the file

 StreamReader sr = new StreamReader(fs);

string s = sr.ReadToEnd();

//close the file

sr.Close();

Console.WriteLine(s);

else

Console.WriteLine("File not found");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

It shows content from �C:\CSharp\sample.txt� file.

C#.NET � Console � ADO.NET
Database Basics

Database Basics

� DBMS (Database Management System): It is a software, which is used to

store and manage databases. Ex: SQL Server, Oracle etc.
� Database: It is a collection of tables. Databases are used to store data
permanently.
� Table: It is a collection of rows and columns.
� Column: A field in the table is called as column.
� Row: A record in the table is called as row.

Table Structure

Sl. No

Column Name

Data Type

Column1

Data type 1

Column2

Data type 2

Column3

Data type 3
Example of Table Structure: Employees

Sl. No

Column Name

Data Type

EmpID

Int

EmpName

Nvarchar(max)

Salary

decimal

Table: Employees

EmpID

EmpName

Salary

Scott

5000

Allen

6000

Jones

7000
4

John

8000

Mark

9000
Introduction to ADO.NET

Introduction to ADO.NET

� ADO.NET (ActiveX Data Objects .NET) is a �database technology� or

�database framework�, which is used to connect and interact with databases
such as SQL Server, Oracle, Excel, Access etc.
� ADO.NET is a collection of pre-defined classes.
� ADO.NET can be used in c#.net and asp.net also.

List of pre-defined classes in ADO.NET

� ADO.NET provides the following pre-defined classes.

1. System.Data.SqlClient.SqlConnection
2. System.Data.SqlClient.SqlCommand
3. System.Data.SqlClient.SqlDataReader
4. System.Data.SqlClient.SqlDataAdapter
5. System.Data.SqlClient.SqlParameter
6. System.Data.SqlClient.SqlCommandBuilder
7. System.Data.SqlClient.SqlTransaction
8. System.Data.OleDb.OleDbConnection
9. System.Data.OleDb.OleDbCommand
10. System.Data.OleDb.OleDbDataReader
11. System.Data.OleDb.OleDbDataAdapter
12. System.Data.OleDb.OleDbParameter
13. System.Data.OleDb.OleDbCommandBuilder
14. System.Data.OleDb.OleDbTransaction
15. System.Data.DataSet
16. System.Data.DataTable
17. System.Data.DataRow
18. System.Data.DataColumn
19. System.Data.DataView
ADO.NET � �SqlConnection� class

System.Data.SqlClient.SqlConnection

� The �SqlConnection� is a class, which is a member of �System.Data.SqlClient�

namespace.
� This class�s object represents a connection to SQL Server database.

Properties of �SqlConnection� class:

Sl.
No

Property

Data Type

Description

ConnectionString

string

Represents details about the

connection, based on which ado.net
should establish a connection with
database.

Syntax:
referencevariable.ConnectionString
= �connection string here�;

State

ConnectionState

Represents current status of the

connection, whether it is opened or
closed. It is readonly property.

Syntax: referencevariable.State
Constructors of �SqlConnection� class:

Sl.
No

Constructor

Description

SqlConnection()

Initializes nothing.

Syntax: new SqlConnection();

SqlConnection(string
ConnectionString)

Initializes �ConnectionString� property.

Syntax: new SqlConnection(�connection string here�);

Methods of �SqlConnection� class:

Sl.
No

Method

Return Data
Type

Description

Open()

void

Opens the connection. After opening the

connection, SQL Server listens the requests you
made.

Syntax: referencevariable.Open()

Close()
void

Closes the connection. After closing the

connection, SQL Server stops listening the
requests you made.

Syntax: referencevariable.Close()

Steps for development of �SqlConnection� class:

� Import the namespace:

o using System.Data.SqlClient;

� Create a reference variable:

o SqlConnection referencevariable;

� Create an object:
o referencevariable = new SqlConnection();
� Set connection string:
o referencevariable.ConnectionString = �connection string here�;

� Open the connection:

o referencevariable.Open( );

� Close the connection:

o referencevariable.Close( );

Connection Strings for SQL Server

Sl.
No

Type of
connection

Description

Connection String

Windows
Authentication

The current working

windows username and
password will be
automatically
submitted to SQL
Server.

�data source=servernamehere ;
integrated security=yes; initial
catalog=databasenamehere�

2
SQL Server
Authentication

We can submit SQL

Server username and
password to SQL
Server.

�data source=servernamehere ;
user id=usernamehere ;
password=passwordhere ; initial
catalog=databasenamehere�
SqlConnection � Windows Authentication �
Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �WindowsAuthExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �WindowsAuthExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace WindowsAuthExample

class Program

static void Main()

//create reference variable

SqlConnection cn;

//create object

cn = new SqlConnection();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

//calling methods
 Console.WriteLine(cn.State); //Output: Closed

cn.Open();

Console.WriteLine(cn.State); //Output: Open

cn.Close();

Console.WriteLine(cn.State); //Output: Closed

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
SqlConnection � SQL Server Authentication
� Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SqlServerAuthExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SqlServerAuthExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace SqlServerAuthExample

class Program

static void Main()

//create reference variable

SqlConnection cn;

//create object

cn = new SqlConnection();

//calling properties

cn.ConnectionString = "data source=localhost; user id=sa;

password=123; initial catalog=company";

//calling methods

Console.WriteLine(cn.State); //Output: Closed

 cn.Open();

Console.WriteLine(cn.State); //Output: Open

cn.Close();

Console.WriteLine(cn.State); //Output: Closed

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
The "SqlCommand" class in ADO.NET

System.Data.SqlClient.SqlCommand

� The �SqlCommand� is a pre-defined class in a namespace called

�System.Data.SqlClient�.
� This class�s object is used to execute an SQL statement or stored procedure
through database connection.
� It requires to use SqlConnection class, to connect with database.
� It requires to use SqlParameter class, to pass parameters to DBMS.

Properties of �SqlCommand� class:

Sl.
No

Property

Data Type

Description

CommandText

string

Represents the sql statement or store

procedure name, which has to be
executed at the DBMS.

Syntax: referencevariable.CommandText
= �sql statement | stored procedure name
here�;

Connection

SqlConnection

Represents the connection object, based

on which the command has to be
executed.

Syntax: referencevariable.Connection =
ReferenceVariableOfSqlConnectionClass;
a) Text = Represents a command with
a normal SQL statement, such as
SELECT | INSERT | UPDATE | DELETE
etc.
b) StoredProcedure = Represents a
command with stored procedure.

CommandType

CommandType

Represents type of the command.

Options: Text | StoredProcedure

Syntax: referencevariable.CommandType
=
System.Data.CommandType.Optionhere;

Parameters

List<SqlParameter>

Represents the collection of parameters

that are to be passed to DBMS in order to
execute the command.

Syntax:
referencevariable.Parameters.Add(ReferenceVariableOfSqlParameter)

Transaction

SqlTransaction

Represents the transaction, in which the

command is a part.

Syntax: referencevariable.Transaction =
ReferenceVariableOfSqlTransaction;

Constructors of �SqlCommand� class:

Sl.
No
Constructor

Description

SqlCommand()

Initializes nothing.

Syntax: new SqlCommand();

SqlCommand(string
CommandText,
SqlConnection
connection)

Initializes �CommandText� and �Connection�

properties.

Syntax: new SqlCommand(�command text here�, cn);

Methods of �SqlCommand� class:

Sl.
No

Method

Return Data
Type

Description

ExecuteScalar()

object

Executes the SELECT statement and

returns only one result value.

This method requires the connection

in �Open� status.

Syntax:
referencevariable.ExecuteScalar()

ExecuteReader()

SqlDataReader

Executes the SELECT statement &

creates and returns an object of
SqlDataReader class.

This method requires the connection

in �Open� status.

Syntax:
referencevariable.ExecuteReader()

ExecuteNonQuery(
)

int

Executes the INSERT | UPDATE |

DELETE statement & returns the no.
of rows affected.

This method requires the connection

in �Open� status.

Syntax:
referencevariable.ExecuteNonQuery()
ADO.NET - ExecuteScalar

ExecuteScalar

� �ExecuteScalar� method is used to execute a �SELECT statement� or �stored

procedure� and get the single result value.

Steps for development of �ExecuteScalar� method:

� Import the namespace:

o using System.Data.SqlClient;

� Create reference variables:

o SqlConnection cn;
o SqlCommand cmd;

� Create objects:
o cn = new SqlConnection();
o cmd = new SqlCommand();

� Call properties
o cmd.CommandText = �comamd text here�;
o cmd.Connection = cn;

� Call methods
o cn.Open();
o object variablename = cmd.ExecuteScalar( );
o cn.Close();
SqlCommand � ExecuteScalar � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ExecuteScalarExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ExecuteScalarExample�. Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace ExecuteScalarExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

/* create objects */

cn = new SqlConnection();

cmd = new SqlCommand();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";
 cmd.CommandText = "select EmpName from Employees where
EmpID=1";

cmd.Connection = cn;

/* call methods */

cn.Open();

object obj = cmd.ExecuteScalar();

cn.Close();

string n = Convert.ToString(obj);

string msg = "Emp Name: " + n;

Console.WriteLine(msg);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
SqlCommand � ExecuteScalar � Example 2

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ExecuteScalarExample2�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ExecuteScalarExample2�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace ExecuteScalarExample2

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

/* create objects */

cn = new SqlConnection();

cmd = new SqlCommand();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";
 cmd.CommandText = "select count(*) from Employees";

cmd.Connection = cn;

/* call methods */

cn.Open();

object obj = cmd.ExecuteScalar();

cn.Close();

string n = Convert.ToString(obj);

Console.WriteLine("Emps Count: " + n);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � Connection Oriented Model �
Introduction

ADO.NET Connection Oriented Model

� The �ADO.NET Connection Oriented Model� concept is used to read the

data from database in �record-by-record� (row-by-row) approach.
� ADO.NET sends request to the database server and gets only one record at-
a-time. It stores the current record in an object of �SqlDataReader� class.
� The connection should be in �Open� status, while retrieving data from
database.

Advantages of Connection Oriented Model:

� At-a-time ONLY ONE record will be stored in .net application memory

(RAM). So it requires less amount of memory.

Dis-advantages of Connection Oriented Model:

� It is a bit slow-process because of �record-by-record� approach.

� It supports �sequential retrieval of records�. We can�t retrieve a record
based on its index. We can�t retrieve records randomly or in reverse order.
List of classes required for ADO.NET Connection Oriented
Model:

1. System.Data.SqlClient.SqlConnection
o Used to connect with SQL Server.

2. System.Data.SqlClient.SqlCommand
o Used to send and execute an SQL statement to SQL Server.

3. System.Data.SqlClient.SqlDataReader
o Used to read records one-by-one.
The "SqlDataReader" class in ADO.NET

System.Data.SqlClient.SqlDataReader

� The �SqlDataReader� is a pre-defined class in a namespace called

�System.Data.SqlClient�.
� This class�s object is used to store a single record, while retrieving data from
database in �ADO.NET Connection Oriented Model�.
� It occupies the memory, which is enough for storing single database record.
� �SqlDataReader� is useful only in �ADO.NET Connection Oriented Model�.

Properties of �SqlDataReader� class:

Sl.
No

Property

Data
Type

Description

[column index]

object

Retrieves the column value in the current

record, based on the column index.

Syntax: referencevariable [column index]

[�column name�]

object

Retrieves the column value in the current

record, based on the column name.

Syntax: referencevariable [�column name�]

FieldCount

int

Represents the no. of fields (columns) in the

current record.

Syntax: referencevariable.FieldCount
4

HasRows

bool

Represents a Boolean value, whether the

datareader object has any rows or not.

Syntax: referencevariable.HasRows

Constructors of �SqlDataReader� class:

Sl.
No

Constructor

Description

No constructors

Methods of �SqlDataReader� class:

Sl.
No

Method

Return
Data
Type

Description

Read()

bool

Reads the next record into the

DataReader.

It returns �true�, if data found.

It returns �false�, if it is reached to

end of records.

Syntax: referencevariable.Read()

GetValue(int columnindex)

object

Returns the value of the specified

column in the current record.

Syntax:
referencevariable.GetValue(int
columnindex)
ADO.NET � Connection Oriented Model

Steps for development of �ADO.NET Connection Oriented

Model�:

� Import the namespace:

o using System.Data.SqlClient;

� Create reference variables:

o SqlConnection cn;
o SqlCommand cmd;
o SqlDataReader dr;

� Create objects:
o cn = new SqlConnection();
o cmd = new SqlCommand();

Note: We are creating an object for �SqlDataReader�

class; because it will be created automatically when
we call ExecuteReader() method.
� Call properties
o cmd.CommandText = �comamd text here�;
o cmd.Connection = cn;

� Call methods
o cn.Open();
o dr = cmd.ExecuteReader( );
o dr.Read();
o dr[�column name�];
o cn.Close();
ADO.NET Connection Oriented Model �
Single Record � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �COMSingleRecordExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �COMSingleRecordExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace COMSingleRecordExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataReader dr;

/* create objects */

cn = new SqlConnection();

cmd = new SqlCommand();

/* call properties */
 cn.ConnectionString = "data source=localhost; integrated
security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees where empid=1";

cmd.Connection = cn;

/* call methods */

cn.Open();

dr = cmd.ExecuteReader();

if (dr.Read())

object obj1, obj2, obj3;

obj1 = dr["EmpID"];

obj2 = dr["EmpName"];

obj3 = dr["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

Console.WriteLine("EmpID: " + eid);

Console.WriteLine("EmpName: " + ename);

Console.WriteLine("Salary: " + sal);

cn.Close();

Console.ReadKey();

}
}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Connection Oriented Model �
Multiple Records � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �COMMultipleRecordsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �COMMultipleRecordsExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace COMMultipleRecordsExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataReader dr;

/* create objects */

cn = new SqlConnection();

cmd = new SqlCommand();

/* call properties */
 cn.ConnectionString = "data source=localhost; integrated
security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

/* call methods */

cn.Open();

dr = cmd.ExecuteReader();

while (dr.Read())

object obj1, obj2, obj3;

obj1 = dr["EmpID"];

obj2 = dr["EmpName"];

obj3 = dr["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

Console.WriteLine("EmpID: " + eid + "\nEmpName: " + ename +

"\nSalary: " + sal + "\n");

cn.Close();

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
The "SqlParameter" class in ADO.NET

System.Data.SqlClient.SqlParameter

� The �SqlParameter� is a pre-defined class in a namespace called

�System.Data.SqlClient�.
� This class�s object represents a parameter (name and value), that is to be
passed to DBMS for execution of command.
� It is useful allover in ADO.NET, such as ExecuteScalar, Connection Oriented
Model, Disconnected Model, Non Query Operations, Stored Procedures,
Transactions etc.

Properties of �SqlParamter� class:

Sl.
No

Property

Data Type

Description

ParameterName

string

Represents name of the parameter.

Syntax:
referencevariable.ParameterName
= �parameter name here�

Value

object

Represents the actual value of the

parameter.

Syntax: referencevariable.Value

DbType

DbType

Represents the database data type

of the parameter.
Syntax: referencevariable.DbType =
DbType.Optionhere;
4

Direction

ParameterDirection

Represents direction of the

parameter, whether it has to be
given to DBMS or has to be
retrieved from DBMS.

Options: Input | Output |

InputOutput | ReturnValue

Syntax: referencevariable.Direction
= ParameterDirection.Optionhere;

Constructors of �SqlParameter� class:

Sl.
No

Constructor

Description

SqlParameter()

Initializes nothing.

Syntax: new SqlParameter();

SqlParameter(string
ParameterName, object Value)

Initializes ParameterName and Value

properties.

Syntax: new SqlParameter(�parameter

name here�, value here);
Steps for development of �SqlParameter�:

� Import the namespace:

o using System.Data.SqlClient;

� Create reference variable:

o SqlParameter p;

� Create object:
o p = new SqlParameter();

� Call properties
o p.ParameterName = �parameter name here�;
o p.Value = �value here�;

� Add parameter to command:

o cmd.Parameters.Add(p);
ADO.NET Connection Oriented Model �
SqlParameter � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �COMSqlParameterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �COMSqlParameterExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace COMSqlParameterExample

class Program

static void Main()

//get empid from keyboard

Console.Write("Emp ID: ");

int n = Convert.ToInt32(Console.ReadLine());

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlParameter p1;

SqlDataReader dr;

/* create objects */
 cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees where

empid=@EmpID";

cmd.Connection = cn;

p1.ParameterName = "@EmpID";

p1.Value = n;

cmd.Parameters.Add(p1);

/* call methods */

cn.Open();

dr = cmd.ExecuteReader();

if (dr.Read())

object obj1, obj2;

obj1 = dr["EmpName"];

obj2 = dr["Salary"];

string ename;

decimal sal;

ename = Convert.ToString(obj1);

sal = Convert.ToDecimal(obj2);
Console.WriteLine("Emp Name: " + ename);

Console.WriteLine("Salary: " + sal);

else

{
 Console.WriteLine("No data found");

cn.Close();

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Enter EmpID as �1� and press Enter.

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Disconnected Model

ADO.NET Disconnected Model

� The �System.Data.SqlClient.SqlDataAdapter� class�s object is used to

convert the data from �result-set� format to �data-set� format.
o Resultset = The data (rows and columns) that is returned from SQL
server, after execution of a SELECT statement.
o DataSet = The data that is stored in .net application memory (RAM) in
the form of objects.

� It loads all records at-once.

� �ADO.NET Disconnected Model� is a concept to retrieve data from database.
It is implemented using �SqlDataAdapter�.
� After loading all records at-once, the connection can be closed. That�s why it
is called �ADO.NET Disconnected Model�.

� Advantages of Disconnected Model:

o At-a-time ALL records will be stored (loaded) into .net application
memory (RAM). After that you can disconnect from database. So your
app runs faster.
o We can retrieve a record based on the index.

� Dis-advantages of Disconnected Model:

o ALL records need to be stored in RAM, up to end of the .net
application, so it may be burden on the RAM, if there are so many
records.
. Properties
. SqlCommand SelectCommand: It represents the object of SqlCommand
class, based on which the data is to be retrieved from database.

. Methods
. Fill(DataSet dataset): It executes the SELECT statement, converts the
resultset into dataset and also stores the data in dataset.
. Update(DataSet dataset): It updates the changes made in the dataset
to the database.

. Constructors
. SqlDataAdapter(): It initializes nothing.
. SqlDataAdapter(SqlCommand SelectCommand): It initializes
SelectCommand property.

The �SqlDataAdapter� class

The �System.Data.SqlClient.SqlDataAdapter� class

The �SqlDataAdapter� class has following members:

The �DataSet� class

System.Data.DataSet

� DataSet is used in ADO.NET Disconnected Model.

� DataSet temporarily stores the data that is retrieved from database.
� DataSet internally uses XML.
� DataSet can contains multiple tables.
� Every table in DataSet is treated as an object of �System.Data.DataTable�
class.
� Every column in DataTable is treated as an object of
�System.Data.DataColumn� class.
� Every row in DataTable is treated as an object of �System.Data.DataRow�
class.
DataSet - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DataSetExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DataSetExample�.
� Click on OK.

Program.cs

/* Expected data:

Categories:

CategoryID CategoryName

1 ab

2 cd

Products:

ProductID ProductName Cost

101 prod1 400

102 prd2 500

103 prd3 600

*/

using System;

using System.Data;
namespace DataSetExample

class Program

static void Main()

//creating dataset

DataSet ds = new DataSet();

//creating 2 tables

DataTable dt1 = new DataTable() { TableName = "Categories" };

DataTable dt2 = new DataTable() { TableName = "Products" };

//creating 2 columns for table1

DataColumn col1 = new DataColumn() { ColumnName = "CategoryID",

DataType = typeof(int) };

DataColumn col2 = new DataColumn() { ColumnName =

"CategoryName", DataType = typeof(string) };

//creating 3 columns for table2

DataColumn col3 = new DataColumn() { ColumnName = "ProductID",

DataType = typeof(int) };

DataColumn col4 = new DataColumn() { ColumnName =

"ProductName", DataType = typeof(string) };

DataColumn col5 = new DataColumn() { ColumnName = "Cost",

DataType = typeof(decimal) };

//adding columns to table1

dt1.Columns.Add(col1);

dt1.Columns.Add(col2);

//adding columns to table2

dt2.Columns.Add(col3);

dt2.Columns.Add(col4);

dt2.Columns.Add(col5);
//creating 2 rows for table1

DataRow drow1 = dt1.NewRow();

DataRow drow2 = dt1.NewRow();

//creating 3 rows for table2

DataRow drow3 = dt2.NewRow();

DataRow drow4 = dt2.NewRow();

DataRow drow5 = dt2.NewRow();

//adding rows to table1

dt1.Rows.Add(drow1);

dt1.Rows.Add(drow2);

//adding rows to table2

dt2.Rows.Add(drow3);

dt2.Rows.Add(drow4);

dt2.Rows.Add(drow5);

//adding tables to dataset

ds.Tables.Add(dt1);

ds.Tables.Add(dt2);

/************* setting data **************/

//setting data in table1

dt1.Rows[0]["CategoryID"] = 1;

dt1.Rows[0]["CategoryName"] = "ab";
dt1.Rows[1]["CategoryID"] = 2;

dt1.Rows[1]["CategoryName"] = "cd";

//setting data in table2

dt2.Rows[0]["ProductID"] = 101;

dt2.Rows[0]["ProductName"] = "prod1";
 dt2.Rows[0]["Cost"] = 400;

dt2.Rows[1]["ProductID"] = 102;

dt2.Rows[1]["ProductName"] = "prod2";

dt2.Rows[1]["Cost"] = 500;

dt2.Rows[2]["ProductID"] = 103;

dt2.Rows[2]["ProductName"] = "prod3";

dt2.Rows[2]["Cost"] = 600;

//getting data from table1

Console.WriteLine(dt1.TableName + ": ");

for (int i = 0; i < dt1.Rows.Count; i++)

Console.WriteLine(dt1.Rows[i]["CategoryID"] + ", " +

dt1.Rows[i]["CategoryName"]);

Console.WriteLine();

//getting data from table2

Console.WriteLine(dt2.TableName + ": ");

for (int i = 0; i < dt2.Rows.Count; i++)

Console.WriteLine(dt2.Rows[i]["ProductID"] + ", " +

dt2.Rows[i]["ProductName"] + ", " + dt2.Rows[i]["Cost"]);

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Disconnected Model � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DisconnectedModelExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DisconnectedModelExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace DisconnectedModelExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new SqlConnection();
 cmd = new SqlCommand();

adp = new SqlDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);
Console.WriteLine(eid + ", " + ename + ", " + sal);

Console.ReadKey();
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Disconnected Model � Multiple
Tables - Example

Creating Database

� Note: Ignore this step, if you have created

�departmentsandemployeesdatabase� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database departmentsandemployeesdatabase

go

use departmentsandemployeesdatabase

go

create table Departments(

DeptNo int primary key,

DeptName nvarchar(max),

Loc nvarchar(max))

go

create table Employees(

EmpID int primary key,

EmpName varchar(max),

Salary decimal,

DeptNo int references Departments(DeptNo))

go

insert into Departments values(10, 'Acounting', 'New York')

insert into Departments values(20, 'Operations', 'New Delhi')

insert into Departments values(30, 'Sales', 'New Jersy')

insert into Employees values(1, 'Scott', 3000, 10)
insert into Employees values(2, 'Allen', 6500, 10)

insert into Employees values(3, 'Jones', 4577, 20)

insert into Employees values(4, 'James', 9500, 20)

insert into Employees values(5, 'Smith', 3345, 30)

insert into Employees values(6, 'Harry', 2500, 30)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MultipleTablesExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MultipleTablesExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace MultipleTablesExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;

DataSet ds;

DataTable dt1, dt2;

DataRow drow;

/* create objects */

cn = new SqlConnection();
 cmd = new SqlCommand();

adp = new SqlDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=departmentsandemployeesdatabase";

cmd.CommandText = "select * from Departments select * from

Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

/* departments */

Console.WriteLine("Departments:");

dt1 = ds.Tables[0];

int n = 50;

for (int i = 0; i < dt1.Rows.Count; i++)

drow = dt1.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["DeptNo"];

obj2 = drow["DeptName"];

obj3 = drow["Loc"];

int dno;

string dname;
string loc;

dno = Convert.ToInt32(obj1);

dname = Convert.ToString(obj2);

loc = Convert.ToString(obj3);
Console.WriteLine(dno + ", " + dname + ", " + loc);

/* employees */

Console.WriteLine("\nEmployees:");

dt2 = ds.Tables[1];

n += 100;

for (int i = 0; i < dt2.Rows.Count; i++)

drow = dt2.Rows[i];

object obj1, obj2, obj3, obj4;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

obj4 = drow["DeptNo"];

int eid;

string ename;

decimal sal;

int dno;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

dno = Convert.ToInt32(obj4);
Console.WriteLine(eid + ", " + ename + ", " + sal + ", " + dno);

Console.ReadKey();

}
}

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Disconnected Model � Joins -
Example

Creating Database

� Note: Ignore this step, if you have created

�departmentsandemployeesdatabase� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database departmentsandemployeesdatabase

go

use departmentsandemployeesdatabase

go

create table Departments(

DeptNo int primary key,

DeptName nvarchar(max),

Loc nvarchar(max))

go

create table Employees(

EmpID int primary key,

EmpName varchar(max),

Salary decimal,

DeptNo int references Departments(DeptNo))

go

insert into Departments values(10, 'Acounting', 'New York')

insert into Departments values(20, 'Operations', 'New Delhi')

insert into Departments values(30, 'Sales', 'New Jersy')

insert into Employees values(1, 'Scott', 3000, 10)
insert into Employees values(2, 'Allen', 6500, 10)

insert into Employees values(3, 'Jones', 4577, 20)

insert into Employees values(4, 'James', 9500, 20)

insert into Employees values(5, 'Smith', 3345, 30)

insert into Employees values(6, 'Harry', 2500, 30)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �JoinsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �JoinsExample�.
� Click on OK.
Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace JoinsExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=departmentsandemployeesdatabase";

cmd.CommandText = "select * from employees inner join

departments on employees.deptno=departments.deptno";
cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */
adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3, obj4, obj5, obj6;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

obj4 = drow["DeptNo"];

obj5 = drow["DeptName"];

obj6 = drow["Loc"];

int eid;

string ename;

decimal sal;

int dno;

string dname;

string loc;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

dno = Convert.ToInt32(obj4);

dname = Convert.ToString(obj5);

loc = Convert.ToString(obj6);

Console.WriteLine(eid + ", " + ename + ", " + sal + ", " + dno + ", " + loc);

Console.ReadKey();

}
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query - Insertion � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InsertionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InsertionExample�. Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace InsertionExample

class Program

static void Main()

//create reference variables

SqlConnection cn;

SqlCommand cmd;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "insert into Employees values(10, 'qwerty',

4500)";

cmd.Connection = cn;
 //calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows inserted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query - Updation � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �UpdationExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �UpdationExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace UpdationExample

class Program

static void Main()

//create reference variables

SqlConnection cn;

SqlCommand cmd;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "update Employees set EmpName='asdf',

Salary=8900 where EmpID=1";
 cmd.Connection = cn;

//calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows updated");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query - Deletion � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DeletionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DeletionExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace DeletionExample

class Program

static void Main(string[] args)

//create reference variables

SqlConnection cn;

SqlCommand cmd;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "delete from Employees where EmpID=3";

cmd.Connection = cn;
 //calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows deleted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query � Insertion � With
SqlParameter � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InsertionSqlParameterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InsertionSqlParameterExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace InsertionSqlParameterExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;

SqlParameter p1, p2, p3;

 //create objects

cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

p2 = new SqlParameter();

p3 = new SqlParameter();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "insert into Employees values(@empid,

@empname, @salary)";

cmd.Connection = cn;

p1.ParameterName = "@empid";

p2.ParameterName = "@empname";

p3.ParameterName = "@salary";

p1.Value = empId;

p2.Value = empName;

p3.Value = sal;

cmd.Parameters.Add(p1);

cmd.Parameters.Add(p2);

cmd.Parameters.Add(p3);

//calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows inserted");

 Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query � Updation � With
SqlParameter � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �UpdationSqlParameterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �UpdationSqlParameterExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace UpdationSqlParameterExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;

SqlParameter p1, p2, p3;

//create objects
 cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

p2 = new SqlParameter();

p3 = new SqlParameter();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "update Employees set empname=@empname,

salary=@salary where empid=@empid";

cmd.Connection = cn;

p1.ParameterName = "@empid";

p2.ParameterName = "@empname";

p3.ParameterName = "@salary";

p1.Value = empId;

p2.Value = empName;

p3.Value = sal;

cmd.Parameters.Add(p1);

cmd.Parameters.Add(p2);

cmd.Parameters.Add(p3);

//calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows updated");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query � Deletion � With
SqlParameter � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DeletionSqlParameterExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DeletionSqlParameterExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace DeletionSqlParameterExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;

SqlParameter p1;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

 p1 = new SqlParameter();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "delete from Employees where empid=@empid";

cmd.Connection = cn;

p1.ParameterName = "@empid";

p1.Value = empId;

cmd.Parameters.Add(p1);

//calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows deleted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
Stored Procedures Calling in ADO.NET

Calling Stored Procedures using ADO.NET

� Stored procedure is a collection of SQL statements that will be stored in

database.
� Stored procedures can be called from .net application.
� Stored procedures will be compiled once and executes every time when we
call it. This is called �pre-compilation�.
� Stored procedures improve performance because of pre-compilation.
� Stored procedures support to separate work between database developer
and .net developer in real time.
� Stored procedures are best for performing multiple and complex database
operations with a single database call.

Syntax of creating stored procedure in SQL Server

create procedure procedurename

(@parameter1 datatype, @parameter2 datatype, �)

as begin

code here

end

go
ADO.NET Non Query � Insertion � With
Stored Procedures � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go
create procedure InsertEmployee(

@EmpID int,

@EmpName nvarchar(max),

@Salary decimal

as begin

insert into Employees values(@EmpID, @EmpName, @Salary)

end

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �InsertionWithSPExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �InsertionWithSPExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace InsertionWithSPExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;
 SqlParameter p1, p2, p3;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

p2 = new SqlParameter();

p3 = new SqlParameter();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "InsertEmployee";

cmd.Connection = cn;

cmd.CommandType = CommandType.StoredProcedure;

p1.ParameterName = "@empid";

p2.ParameterName = "@empname";

p3.ParameterName = "@salary";

p1.Value = empId;

p2.Value = empName;

p3.Value = sal;

cmd.Parameters.Add(p1);

cmd.Parameters.Add(p2);

cmd.Parameters.Add(p3);

//calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();
 Console.WriteLine(n + " rows inserted");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query � Updation � With
Stored Procedures � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go
create procedure UpdateEmployee(

@EmpID int,

@EmpName nvarchar(max),

@Salary decimal

as begin

update Employees set EmpName=@EmpName, Salary=@Salary

where EmpID=@EmpID

end

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �UpdationWithSPExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �UpdationWithSPExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace UpdationWithSPExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;
 SqlParameter p1, p2, p3;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

p2 = new SqlParameter();

p3 = new SqlParameter();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "UpdateEmployee";

cmd.Connection = cn;

cmd.CommandType = CommandType.StoredProcedure;

p1.ParameterName = "@empid";

p2.ParameterName = "@empname";

p3.ParameterName = "@salary";

p1.Value = empId;

p2.Value = empName;

p3.Value = sal;

cmd.Parameters.Add(p1);

cmd.Parameters.Add(p2);

cmd.Parameters.Add(p3);

//calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();
 Console.WriteLine(n + " rows updated");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET Non Query � Deletion � With
Stored Procedures � Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go
create procedure DeleteEmployee(

@EmpID int

as begin

delete from Employees

where EmpID=@EmpID

end

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DeletionWithSPExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DeletionWithSPExample�.
� Click on OK.
Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace DeletionWithSPExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;

SqlParameter p1;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "DeleteEmployee";

cmd.Connection = cn;
cmd.CommandType = CommandType.StoredProcedure;

p1.ParameterName = "@empid";

p1.Value = empId;

cmd.Parameters.Add(p1);
 //calling methods

cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

Console.WriteLine(n + " rows deleted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET - Transactions

ADO.NET Transactions

� A transaction is a �collection of database operations such as insertion,

deletion and updation�.
� ADO.NET transactions are used to roll back the previously executed
database operations, when any database operation is failed in a transaction.
� Example: Funds transfer from one bank account to another bank account.
. Operation 1: Debit the money from source account.
. Operation 2: Credit the money to destination account.

� We use �System.Data.SqlClient.SqlTransaction� class is used to implement

ado.net transactions in the program.
1. cn.BeginTransaction()
. This method creates and starts a new ado.net transaction. It creates and
returns an object for �SqlTransaction� class.

2. transactionReferenceVariable.Commit()
. This method will save (fix) the database operations that are executed
during the current transaction.

3. transactionReferenceVariable.RollBack()
. This method will rollback (cancel) all the previously executed database
operations during the current transaction.

Methods for ADO.NET Transactions:

ADO.NET � Transactions - Example

Creating Database

� Note: Ignore this step, if you have created �transactionsdatabase� database

already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database transactionsdatabase

go

use transactionsdatabase

go

CREATE TABLE AccountsTable(

AccountNo int primary key,

AccountHolderName nvarchar(40),

Balance decimal)

GO

INSERT INTO AccountsTable VALUES (101, 'scott', 10000)

INSERT INTO AccountsTable VALUES (102, 'allen', 5000)

GO

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �TransactionsExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �TransactionsExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

namespace TransactionsExample

class Program

static void Main()

//create reference variables

SqlConnection cn;

SqlTransaction transaction;

SqlCommand cmd1, cmd2;

//create objects

cn = new SqlConnection();

cmd1 = new SqlCommand();

cmd2 = new SqlCommand();

//call properties
 cn.ConnectionString = "data source=localhost; integrated
security=yes; initial catalog=transactionsdatabase";

cmd1.CommandText = "update AccountsTable set Balance=Balance-

1000 where AccountNo=101";

cmd2.CommandText = "update AccountsTable set

Balance=Balance+1000 were AccountNo=102";

cmd1.Connection = cn;

cmd2.Connection = cn;

//call methods

cn.Open();

transaction = cn.BeginTransaction();

cmd1.Transaction = transaction;

cmd2.Transaction = transaction;

try

cmd1.ExecuteNonQuery();

Console.WriteLine("First operation done.");

cmd2.ExecuteNonQuery();

Console.WriteLine("Second operation done.");

transaction.Commit(); //save data

Console.WriteLine("Transaction Complete");

catch (Exception)

transaction.Rollback(); //first operation will be rollback

Console.WriteLine("Rollback done!");

}
cn.Close();

Console.ReadKey();

}
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
The "OleDb" namespace in ADO.NET

System.Data.OleDb (Object Linking and Embedding

Database)

� The �System.Data.OleDb� namespace contains classes like

OleDbConnection, OleDbCommand etc. The usage of these classes are same
as SqlConnectoin, SqlCommand etc.
� The System.Data.OleDb namespace is used to connect and interact with
various databases like Oracle, Excel, Access etc.

Classes in �System.Data.OleDb� namespace

Sl.
No

SqlClient namespace

(For SQL Server)

�OleDb� namespace

(For Oracle, Excel, Access)

System.Data.SqlClient.SqlConnection

System.Data.OleDb.OleDbConnection

System.Data.SqlClient.SqlCommand

System.Data.OleDb.OleDbCommand

System.Data.SqlClient.SqlDataReader

System.Data.OleDb.OleDbDataReader

System.Data.SqlClient.SqlParameter

System.Data.OleDb.OleDbParameter

System.Data.SqlClient.SqlDataAdapter

System.Data.OleDb.OleDbDataAdapter

6
System.Data.SqlClient.SqlCommandBuilder

System.Data.OleDb.OleDbCommandBuilder

System.Data.SqlClient.SqlTransaction

System.Data.OleDb.OleDbTransaction

System.Data.DataSet

System.Data.DataSet

System.Data.DataTable

System.Data.DataTable

10

System.Data.DataRow

System.Data.DataRow

11

System.Data.DataColumn

System.Data.DataColumn
Connection Strings in ADO.NET

Connection string for SQL Server

� "data source=Servernamehere; integrated security=yes; initial

catalog=Databasenamehere"

(or)

� "data source=Servernamehere; user id=Usernamehere;

password=Passwordhere; initial catalog=Databasenamehere"

Connection string for Oracle

� "provider=msdaora.1; user id=Usernamehere; password=Passwordhere"

Connection string for MS Access

� @"provider=Microsoft.Ace.Oledb.12.0; data source=FilePathHere"

Connection string for MS Excel

� @"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=FilePathHere;

Extended Properties='Excel 12.0;HDR=Yes;IMEX=1' "
ADO.NET � Oracle - Example

Installing Oracle Database 11g Expression Edition

� Note: Ignore this step, if you have installed �Oracle 11g Express� already.
� You can download Oracle 11g Express Edition at:
http://www.oracle.com/technetwork/database/database-
technologies/express-edition/downloads/index.html
� Open �Oracle 11g Express� folder.

� Double click on �setup.exe�.

� Click on �Yes�.
� Please wait while it loads�

� Click on �Next�.
� Click on �I accept the terms in the license agreement�.

� Click on �Next�.
� Click on �Next�.

� Enter the password as �123�.

� Enter the confirm password �123�.
� Click on �Next�.

� Click on �Install�.
� Installation may take around 10 minutes.
o Click on OK if it shows one or two errors while installing.
� Click on �Finish�.
� Restart the PC.

Creating table in Oracle

� Note: Ignore this step, if you have created �employees� table in Oracle
already.
� Go to �Start� � �Oracle 11g Express Edition� � �Run SQL Command Line�.
� Type the following script and press Enter.

connect system/123;

create table Employees(

EmpID int primary key,

EmpName varchar2(40),

Salary decimal);

insert into Employees values(1, 'scott', 1040);

insert into Employees values(2, 'james', 9821);

insert into Employees values(3, 'jones', 7721);

commit;
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �OracleExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �OracleExample�.
� Click on OK.

Program.cs

using System;

using System.Data.OleDb;

using System.Data;

namespace OracleExample

class Program

static void Main()

/* create reference variables */

OleDbConnection cn;

OleDbCommand cmd;

OleDbDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new OleDbConnection();

cmd = new OleDbCommand();

 adp = new OleDbDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "user id=system; password=123;

provider=msdaora.1";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

Console.WriteLine(eid + ", " + ename + ", " + sal);

Console.ReadKey();

}
 }

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � MS Access - Example

Installing Access Database Engine

� Install MS Office 2007 or 2010 or 2013 or 2016. You can download MS Office
2016 at: https://support.office.com/en-us/article/Download-and-install-or-
reinstall-Office-365-Office-2016-or-Office-2013-on-your-PC-or-Mac-
4414eaaf-0478-48be-9c42-23adc4716658?ui=en-US&rs=en-US&ad=US
� Additionally, we have to install �Access Database Engine�.
� Note: Ignore this step, if you have installed �Access Database Engine�
already.
� You can download �MS Access Database Engine� at:
https://www.microsoft.com/en-in/download/details.aspx?id=13255
� To install �Access Database Engine�, go to �Access Database Engine� folder.

� Double click on �AccessDatabaseEngine�.

� Click on �Yes�.
� Check the checkbox �I accept the terms in the License Agreement�.
� Click on �Next�.
� Click on �Install�.
� Installation may take around 1 or 2 minutes.

� Click on OK.
Creating table in MS Access

� Go to �Start� � �Access 2016�.

� Click on �Blank desktop database�.

� Type the file name as �Database1.accdb�.

� Click on the folder icon and select �C:\CSharp� folder.

� Click on OK.

� Click on �Create�.
� Right click on �Table1� and click on �Design View�.

� Type the table name as �Employees�.

� Click on OK.
� Type the table structure as follows:

� Right click �Employees� and click on �Open�.

� Click on �Yes�.

� Type the data as follows:

� Save the file.
� Close �Microsoft Access 2016�.
� Make sure �Database1.accdb� file exist in �C:\CSharp� folder.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MSAccessExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MSAccessExample�.
� Click on OK.

Program.cs

using System;

using System.Data.OleDb;

using System.Data;

namespace MSAccessExample

class Program

static void Main()

/* create reference variables */

OleDbConnection cn;

OleDbCommand cmd;

OleDbDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new OleDbConnection();

cmd = new OleDbCommand();

 adp = new OleDbDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = @"provider=Microsoft.Ace.Oledb.12.0; data

source=C:\CSharp\Database1.accdb";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

Console.WriteLine(eid + ", " + ename + ", " + sal);

Console.ReadKey();

}
 }

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � MS Excel - Example

Installing Access Database Engine

� Install MS Office 2007 or 2010 or 2013 or 2016. You can download MS Office
2016 at: https://support.office.com/en-us/article/Download-and-install-or-
reinstall-Office-365-Office-2016-or-Office-2013-on-your-PC-or-Mac-
4414eaaf-0478-48be-9c42-23adc4716658?ui=en-US&rs=en-US&ad=US
� Additionally, we have to install �Access Database Engine�.
� Note: Ignore this step, if you have installed �Access Database Engine�
already.
� You can download �MS Access Database Engine� at:
https://www.microsoft.com/en-in/download/details.aspx?id=13255
� To install �Access Database Engine�, go to �Access Database Engine� folder.

� Double click on �AccessDatabaseEngine�.

� Click on �Yes�.
� Check the checkbox �I accept the terms in the License Agreement�.
� Click on �Next�.
� Click on �Install�.
� Installation may take around 1 or 2 minutes.

� Click on OK.
Creating work book in MS Excel

� Go to �Start� � �Excel 2016�.

� Click on �Blank Workbook�.

� Type the data as follows:

� Go to �File� � �Save� � �This PC� � �Browse�.

� Select the folder as �C:\CSharp�.
� Type the filename as �Book1.xlsx�.
� Click on �Save�.
� Close �Microsoft Excel 2016�.
� Make sure �Book1.xlsx� file exist in �C:\CSharp� folder.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �MSExcelExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �MSExcelExample�.
� Click on OK.

Program.cs

using System;

using System.Data.OleDb;

using System.Data;

namespace MSExcelExample

class Program

static void Main()

/* create reference variables */

OleDbConnection cn;

OleDbCommand cmd;

OleDbDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new OleDbConnection();

cmd = new OleDbCommand();

 adp = new OleDbDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data

Source=C:\CSharp\Book1.xlsx; Extended Properties='Excel
12.0;HDR=Yes;IMEX=1' ";

cmd.CommandText = "select * from [Sheet1$]";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

Console.WriteLine(eid + ", " + ename + ", " + sal);

Console.ReadKey();
 }

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � SQL Server to Oracle - Example

Creating SQL Server Database

� Note: Ignore this step, if you have created �company� database in SQL
Server, already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Installing Oracle Database 11g Expression Edition

� Install �Oracle 11g Express� as shown in the previous example.

� You can download Oracle 11g Express Edition at:
http://www.oracle.com/technetwork/database/database-
technologies/express-edition/downloads/index.html

Creating table in Oracle

� Note: Ignore this step, if you have created �employees2� table in Oracle
already.
� Go to �Start� � �Oracle 11g Express Edition� � �Run SQL Command Line�.
� Type the following script and press Enter.

connect system/123;

create table Employees2(

EmpID int,

EmpName varchar2(40),

Salary decimal);

commit;
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SqlServerToOracleExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SqlServerToOracleExample�.
� Click on OK.
Program.cs

//Copy data from "SqlServer" to "Oracle"

using System;

using System.Data.SqlClient;

using System.Data.OleDb;

using System.Data;

namespace SqlServerToOracleExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";
cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;
/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

InsertIntoOracle(eid, ename, sal);

Console.WriteLine(dt.Rows.Count + " records copied");

Console.ReadKey();

private static void InsertIntoOracle(int eid, string ename, decimal sal)

{
//create reference variables

OleDbConnection cn;

OleDbCommand cmd;

//create objects

cn = new OleDbConnection();
 cmd = new OleDbCommand();

//calling properties

cn.ConnectionString = "user id=system; password=123;

provider=msdaora.1";

cmd.CommandText = string.Format("insert into Employees2

values({0}, '{1}', {2})", eid, ename, sal);

cmd.Connection = cn;

//calling methods

cn.Open();

cmd.ExecuteNonQuery();

cn.Close();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
Check the data in �Oracle�:
ADO.NET � SQL Server to MS Excel - Example

Creating SQL Server Database

� Note: Ignore this step, if you have created �company� database in SQL
Server, already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Installing Access Database Engine

� Install MS Office 2007 or 2010 or 2013 or 2016. You can download MS Office
2016 at: https://support.office.com/en-us/article/Download-and-install-or-
reinstall-Office-365-Office-2016-or-Office-2013-on-your-PC-or-Mac-
4414eaaf-0478-48be-9c42-23adc4716658?ui=en-US&rs=en-US&ad=US
� Additionally, we have to install �Access Database Engine�, based on the
steps explained in the previous examples.
� Note: Ignore this step, if you have installed �Access Database Engine�
already.
� You can download �MS Access Database Engine� at:
https://www.microsoft.com/en-in/download/details.aspx?id=13255
Creating work book in MS Excel

� Go to �Start� � �Excel 2016�.

� Click on �Blank Workbook�.

� Type the data as follows:

� Go to �File� � �Save� � �This PC� � �Browse�.

� Select the folder as �C:\CSharp�.
� Type the filename as �Book2.xlsx�.
� Click on �Save�.
� Close �Microsoft Excel 2016�.
� Make sure �Book2.xlsx� file exist in �C:\CSharp� folder.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SqlServerToExcelExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SqlServerToExcelExample�.
� Click on OK.

Program.cs

//Copy data from "SqlServer" to "Excel"

using System;

using System.Data.SqlClient;

using System.Data.OleDb;

using System.Data;

namespace SqlServerToExcelExample

class Program

static void Main()

/* create reference variables */

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */
 cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);
sal = Convert.ToDecimal(obj3);

InsertIntoExcel(eid, ename, sal);

}
 Console.WriteLine(dt.Rows.Count + " records copied");

Console.ReadKey();

private static void InsertIntoExcel(int eid, string ename, decimal sal)

//create reference variables

OleDbConnection cn;

OleDbCommand cmd;

//create objects

cn = new OleDbConnection();

cmd = new OleDbCommand();

//calling properties

cn.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data

Source=C:\CSharp\Book2.xlsx; Extended Properties='Excel
12.0;HDR=Yes;IMEX=3' ";

cmd.CommandText = string.Format("insert into [Sheet1$] values('{0}',

'{1}', '{2}')", eid, ename, sal);

cmd.Connection = cn;

//calling methods

cn.Open();

cmd.ExecuteNonQuery();

cn.Close();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
� Check the data in �C:\CSharp\Book2.xlsx� file.
ADO.NET � Oracle to SQL Server - Example

Creating SQL Server Database

� Note: Ignore this step, if you have created �company� database with
�Employees2� table in SQL Server, already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees2(

EmpID int,

EmpName nvarchar(max),

Salary decimal)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Installing Oracle Database 11g Expression Edition

� Install �Oracle 11g Express� as shown in the previous example.

� You can download Oracle 11g Express Edition at:
http://www.oracle.com/technetwork/database/database-
technologies/express-edition/downloads/index.html

Creating table in Oracle

� Note: Ignore this step, if you have created �employees2� table in Oracle
already.
� Go to �Start� � �Oracle 11g Express Edition� � �Run SQL Command Line�.
� Type the following script and press Enter.

connect system/123;

create table Employees2(

EmpID int,

EmpName varchar2(40),

Salary decimal);

insert into Employees2 values(1, 'scott', 1040);

insert into Employees2 values(2, 'james', 9821);

insert into Employees2 values(3, 'jones', 7721);

commit;
Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �OracleToSqlServerExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �OracleToSqlServerExample�.
� Click on OK.

Program.cs

//Copy data from "Oracle" to "SqlServer"

using System;

using System.Data.SqlClient;

using System.Data.OleDb;

using System.Data;

namespace OracleToSqlServerExample

class Program

static void Main()

/* create reference variables */

OleDbConnection cn;

OleDbCommand cmd;

OleDbDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */

cn = new OleDbConnection();
cmd = new OleDbCommand();
 adp = new OleDbDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = "user id=system; password=123;

provider=msdaora.1";

cmd.CommandText = "select * from Employees2";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);

ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

InsertIntoSqlServer(eid, ename, sal);

Console.WriteLine(dt.Rows.Count + " records copied");

Console.ReadKey();
 }

private static void InsertIntoSqlServer(int eid, string ename, decimal

sal)

{
 //create reference variables

SqlConnection cn;

SqlCommand cmd;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = string.Format("insert into Employees2

values({0}, '{1}', {2})", eid, ename, sal);

cmd.Connection = cn;

//calling methods

cn.Open();

cmd.ExecuteNonQuery();

cn.Close();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).

Check the data in �SQL Server�:

ADO.NET � Excel to SQL Server - Example

Creating SQL Server Database

� Note: Ignore this step, if you have created �company� database with
�Employees2� table in SQL Server, already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees2(

EmpID int,

EmpName nvarchar(max),

Salary decimal)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Installing Access Database Engine

� Install MS Office 2007 or 2010 or 2013 or 2016. You can download MS Office
2016 at: https://support.office.com/en-us/article/Download-and-install-or-
reinstall-Office-365-Office-2016-or-Office-2013-on-your-PC-or-Mac-
4414eaaf-0478-48be-9c42-23adc4716658?ui=en-US&rs=en-US&ad=US
� Additionally, we have to install �Access Database Engine�, based on the
steps explained in the previous examples.
� Note: Ignore this step, if you have installed �Access Database Engine�
already.
� You can download �MS Access Database Engine� at:
https://www.microsoft.com/en-in/download/details.aspx?id=13255
Creating Workbook in �Excel�:

� Go to �Start� � �Excel 2016�.

� Click on �Blank Workbook�.

� Type the data as follows:

� Go to �File� � �Save� � �This PC� � �Browse�.

� Select the folder as �C:\CSharp�.
� Type the filename as �Book1.xlsx�.
� Click on �Save�.
� Close �Microsoft Excel 2016�.
� Make sure �Book1.xlsx� file exist in �C:\CSharp� folder.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �ExcelToSqlServerExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �ExcelToSqlServerExample�.
� Click on OK.

Program.cs

//Copy data from "Excel" to "SqlServer"

using System;

using System.Data.SqlClient;

using System.Data.OleDb;

using System.Data;

namespace ExcelToSqlServerExample

class Program

static void Main()

/* create reference variables */

OleDbConnection cn;

OleDbCommand cmd;

OleDbDataAdapter adp;

DataSet ds;

DataTable dt;

DataRow drow;

/* create objects */
 cn = new OleDbConnection();

cmd = new OleDbCommand();

adp = new OleDbDataAdapter();

ds = new DataSet();

/* call properties */

cn.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0; Data

Source=C:\CSharp\Book1.xlsx; Extended Properties='Excel
12.0;HDR=Yes;IMEX=1' ";

cmd.CommandText = "select * from [Sheet1$]";

cmd.Connection = cn;

adp.SelectCommand = cmd;

/* call methods */

adp.Fill(ds);

dt = ds.Tables[0];

for (int i = 0; i < dt.Rows.Count; i++)

drow = dt.Rows[i];

object obj1, obj2, obj3;

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid;

string ename;

decimal sal;

eid = Convert.ToInt32(obj1);
ename = Convert.ToString(obj2);

sal = Convert.ToDecimal(obj3);

InsertIntoSqlServer(eid, ename, sal);

}
 Console.WriteLine(dt.Rows.Count + " records copied");

Console.ReadKey();

private static void InsertIntoSqlServer(int eid, string ename, decimal

sal)

//create reference variables

SqlConnection cn;

SqlCommand cmd;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

//calling properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = string.Format("insert into Employees2

values({0}, '{1}', {2})", eid, ename, sal);

cmd.Connection = cn;

//calling methods

cn.Open();

cmd.ExecuteNonQuery();

cn.Close();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
Check the data in �SQL Server�:
ADO.NET � SQL Server to File - Example

Creating SQL Server Database

� Note: Ignore this step, if you have created �company� database with
�Employees2� table in SQL Server, already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees2(

EmpID int,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015. Go to �File� � �New� � �Project�.

� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �SqlServerToFileExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �SqlServerToFileExample�. Click on OK.

Program.cs

//Copy data from "SqlServer" to "File"

using System;

using System.Data.SqlClient;

using System.Data;

using System.Diagnostics;

using System.IO;

namespace SqlServerToFileExample

class Program

static void Main()

//create directory if not exists

if (Directory.Exists(@"C:\CSharp") == false)

Directory.CreateDirectory(@"C:\CSharp");

//create reference variables

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;
DataSet ds;

DataTable dt;
 DataRow drow;

FileInfo finfo;

FileStream fs;

StreamWriter sw;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

ds = new DataSet();

finfo = new FileInfo(@"C:\CSharp\Employees.txt");

//delete the file if already exists

if (finfo.Exists == true)

finfo.Delete();

//create objects

fs = new FileStream(@"C:\CSharp\Employees.txt", FileMode.Create,

FileAccess.Write);

sw = new StreamWriter(fs);

//call properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees2";

cmd.Connection = cn;

adp.SelectCommand = cmd;

//call methods

adp.Fill(ds);
//read data

dt = ds.Tables[0];

//read data from database record-by-record

 for (int i = 0; i < dt.Rows.Count; i++)

//get values

object obj1, obj2, obj3;

drow = dt.Rows[i];

obj1 = drow["EmpID"];

obj2 = drow["EmpName"];

obj3 = drow["Salary"];

int eid = Convert.ToInt32(obj1);

string ename = Convert.ToString(obj2);

double sal = Convert.ToDouble(obj3);

string msg = eid + "," + ename + "," + sal;

//write data to the file

sw.WriteLine(msg);

//close the file

sw.Close();

Console.WriteLine("Data has been written to the following file

successfully.\nC:\\CSharp\\Employees.txt");

//open the file in notepad

Process.Start(@"C:\Windows\System32\notepad.exe",
@"C:\CSharp\Employees.txt");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � File to SQL Server - Example

Creating SQL Server Database

� Note: Ignore this step, if you have created �company� database with
�Employees2� table in SQL Server, already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees2(

EmpID int,

EmpName nvarchar(max),

Salary decimal)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �FileToSqlServerExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FileToSqlServerExample�.
� Click on OK.

Program.cs

//Copy data from "File" to "SqlServer"

using System;

using System.Data.SqlClient;

using System.IO;

namespace FileToSqlServerExample

class Program

static void Main()

//create reference variables

SqlConnection cn;

SqlCommand cmd;

FileInfo finfo;

FileStream fs;

StreamReader sr;

SqlParameter p1, p2, p3;

//create objects

cn = new SqlConnection();
 cmd = new SqlCommand();

p1 = new SqlParameter();

p2 = new SqlParameter();

p3 = new SqlParameter();

finfo = new FileInfo(@"C:\CSharp\Employees.txt");

//check whether the file already exists or not

if (finfo.Exists == false)

Console.WriteLine("File not exists.");

Console.ReadKey();

return;

//create objects

fs = new FileStream(@"C:\CSharp\Employees.txt", FileMode.Open,

FileAccess.Read);

sr = new StreamReader(fs);

//call properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "insert into Employees2 values(@empid,

@empname, @salary)";

cmd.Connection = cn;

//call methods

cmd.Parameters.Add(p1);

cmd.Parameters.Add(p2);

cmd.Parameters.Add(p3);
//read all lines from the file

while (true)

{
//get a line from the file

string line = sr.ReadLine();

string[] values;

values = line.Split(',');

int eid = Convert.ToInt32(values[0]);

string ename = Convert.ToString(values[1]);

double sal = Convert.ToDouble(values[2]);

//set data into parameters

p1.ParameterName = "@empid";

p1.Value = eid;

p2.ParameterName = "@empname";

p2.Value = ename;

p3.ParameterName = "@salary";

p3.Value = sal;

//insert into database

cn.Open();

cmd.ExecuteNonQuery();

cn.Close();

if (sr.EndOfStream == true)

break;

//close the file

sr.Close();
 Console.WriteLine("Data stored into database");

Console.ReadKey();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
Check the data in �SQL Server�:
The "SqlCommandBuilder" class in ADO.NET

System.Data.SqlClient.SqlCommandBuilder

� The �SqlCommandBuilder� is a pre-defined class in a namespace called

�System.Data.SqlClient�.
� This class�s object generates a set of INSERT, UPDATE, DELETE sql
statements automatically, based on the SELECT statement, based on which
we can perform DML operations using DataSet.

Properties of �SqlCommandBuilder� class:

Sl.
No

Property

Data Type

Description

DataAdapter

SqlDataAdapter

Represents the reference of object of

SqlDataAdapter class in which the INSERT,
UPDATE, DELETE commands have to be
generated..

Syntax: referencevariable.DataAdapter =
ReferenceVariableSqlDataAdapter ;

Constructors of �SqlCommandBuilder� class:

Sl.
No

Constructor

Description

SqlCommandBuilder()

Initializes nothing.

Syntax: new SqlCommandBuilder();

2

SqlCommandBuilder
(SqlDataAdapter adapter)

Initializes DataAdapter property.

Syntax: new
SqlCommandBuilder(SqlDataAdapter adapter);
ADO.NET � SqlCommandBuilder � DataSet �
Insertion - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DataSetInsertionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DataSetInsertionExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace DataSetInsertionExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;
 SqlDataAdapter adp;

SqlCommandBuilder cmb;

DataSet ds;

DataTable dt;

DataRow drow;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

cmb = new SqlCommandBuilder();

ds = new DataSet();

//call properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

cmb.DataAdapter = adp;

//call methods

adp.Fill(ds);

dt = ds.Tables[0];

//create a new data row

drow = dt.NewRow();

drow["empid"] = empId;

drow["empname"] = empName;

drow["salary"] = sal;
//add row to the table

dt.Rows.Add(drow);

//save changes back to the database

 adp.Update(ds);

Console.WriteLine("Inserted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � SqlCommandBuilder � DataSet �
Updation - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DataSetUpdationExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DataSetUpdationExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace DataSetUpdationExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;
 SqlDataAdapter adp;

SqlCommandBuilder cmb;

DataSet ds;

DataTable dt;

DataRow drow;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

cmb = new SqlCommandBuilder();

ds = new DataSet();

//call properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

cmb.DataAdapter = adp;

//call methods

adp.Fill(ds);

dt = ds.Tables[0];

//get datarow based on empid

int n = Convert.ToInt32(empId);

string condition = "empid=" + n;

drow = dt.Select(condition)[0];
//update

drow["empname"] = empName;

drow["salary"] = sal;

//save changes back to the database

 adp.Update(ds);

Console.WriteLine("Updated");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
ADO.NET � SqlCommandBuilder � DataSet �
Deletion - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �DataSetDeletionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �DataSetDeletionExample�.
� Click on OK.

Program.cs

using System;

using System.Data.SqlClient;

using System.Data;

namespace DataSetDeletionExample

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

//create reference variables

SqlConnection cn;

SqlCommand cmd;

SqlDataAdapter adp;

SqlCommandBuilder cmb;

DataSet ds;

DataTable dt;
 DataRow drow;

//create objects

cn = new SqlConnection();

cmd = new SqlCommand();

adp = new SqlDataAdapter();

cmb = new SqlCommandBuilder();

ds = new DataSet();

//call properties

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "select * from Employees";

cmd.Connection = cn;

adp.SelectCommand = cmd;

cmb.DataAdapter = adp;

//call methods

adp.Fill(ds);

dt = ds.Tables[0];

//get datarow based on empid

int n = Convert.ToInt32(empId);

string condition = "empid=" + n;

drow = dt.Select(condition)[0];

//delete the row

drow.Delete();

//save changes back to the database

adp.Update(ds);

Console.WriteLine("Deleted");

Console.ReadKey();

}
 }

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
N-Tier Architecture in C#.NET

N-Tier Architecture (or) 3-Tier Architecture

� The application�s code is divided as 3 major parts for ease of maintenance

and administration purpose:
1. Data Access Layer: Contains code for connecting with database.
2. Business Logic Layer: Contains code for validations and calculations.
3. Presentation Layer: Contains code for displaying the UI and event
handling.

� We have to create each �layer (part)� as a separate class library.

N-Tier Architecture - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Solution

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Other Project Types� � �Visual Studio Solutions�.
� Select �Blank Solution�.
� Type the name as �CompanySolution�.
� Type the location as �C:\CSharp�.
� Click on OK.

Creating Data Access Layer

� Open Solution Explorer.

� Right click on the solution (CompanySolution) and click on �Add� � �New
Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#� � �Class Library�.
� Type the name as �CompanyDataAccess�.
� Click on OK.

Creating Business Logic Layer

� Open Solution Explorer.

� Right click on the solution (CompanySolution) and click on �Add� � �New
Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#� � �Class Library�.
� Type the name as �CompanyBusinessLogic�.
� Click on OK.

Creating Presentation Logic

� Open Solution Explorer.
� Right click on the solution (CompanySolution) and click on �Add� � �New
Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#� � �Console Application�.
� Type the name as �CompanyPresentationLogic�.
� Click on OK.

Adding references:

� Open Solution Explorer.

� Right click on �CompanyBusinessLogic� project and click on �Add� �
�Reference� � �Projects� � Check the checkbox �CompanyDataAccess� � OK.
� Right click on �CompanyPresentationLogic� project and click on �Add� �
�Reference� � �Projects� � Check the checkbox �CompanyBusinessLogic� �
OK.

Setting the Startup Project

� Open Solution Explorer.

� Right click on �CompanyPresentationLogic� project and click on �Set as
Startup Project�.
CompanyDataAccess\Class1.cs

//Data Access Logic

using System;

using System.Data.SqlClient;

namespace CompanyDataAccess

public class EmployeesDataAccess

public int InsertEmployee(int EmpID, string EmpName, decimal Salary)

SqlConnection cn;

SqlCommand cmd;

SqlParameter p1, p2, p3;

cn = new SqlConnection();

cmd = new SqlCommand();

p1 = new SqlParameter();

p2 = new SqlParameter();

p3 = new SqlParameter();

cn.ConnectionString = "data source=localhost; integrated

security=yes; initial catalog=company";

cmd.CommandText = "insert into Employees values(@a, @b, @c)";

cmd.Connection = cn;

p1.ParameterName = "@a";

p2.ParameterName = "@b";

p3.ParameterName = "@c";

p1.Value = EmpID;

p2.Value = EmpName;
p3.Value = Salary;

cmd.Parameters.Add(p1);

cmd.Parameters.Add(p2);

cmd.Parameters.Add(p3);
 cn.Open();

int n = cmd.ExecuteNonQuery();

cn.Close();

return n;

CompanyBusinessLogic\Class1.cs

//Business Logic

using System;

using CompanyDataAccess;

namespace CompanyBusinessLogic

public class EmployeesBusinessLogic

private int _empid;

private string _empname;

private decimal _salary;

public int EmpID

set

if (value >= 0)

{
_empid = value;

get

{
return _empid;

public string EmpName

set

if (value.Length <= 40)

_empname = value;

get

return _empname;

public decimal Salary

set

if (value >= 1000 && value <= 5000)

_salary = value;

get
{

return _salary;

public string Insert()

 {

EmployeesDataAccess da = new EmployeesDataAccess();

int result = da.InsertEmployee(this.EmpID, this.EmpName,

this.Salary);

if (result == 1)

return "Inserted";

else

return "Error in insertion";

CompanyPresentationLogic\Program.cs

//Presentation Logic

using System;

using CompanyBusinessLogic;

namespace CompanyPresentationLogic

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

 decimal sal = Convert.ToDecimal(Console.ReadLine());

EmployeesBusinessLogic b = new EmployeesBusinessLogic();

b.EmpID = empId;

b.EmpName = empName;

b.Salary = sal;

string msg = b.Insert();

Console.WriteLine(msg);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
LINQ to SQL

Language Integrated Query (LINQ) to SQL

� �LINQ to SQL� is a framework, which is used to connect and interact with

SQL Server database.
� �LINQ to SQL� was introduced in .NET 3.5.
� �LINQ to SQL� internally uses �ADO.NET� and �SQL�. That means �LINQ to
SQL queries� will be internally converted into �SQL queries� and executed
based on ADO.NET classes.
� �LINQ to SQL� works based on mapping classes. A mapping class represents
the structure of the table. A table become as �mapping class� and all the
columns become as �Properties� in the �mapping class�.
� The �DataContext� class that inherits from �System.Data.Linq.DataContext�
class, represents a group of collections of mapping classes.

Syntax of �LINQ to SQL�:

(from rangevariable in collectionname where condition select

rangevariable).ToList()

-- or �

Collectionname.Where(variable => condition).ToList()

The ToList() method opens the connection, convert the LINQ query into SQL query,
execute the query, convert the resultset into collection and close the database
connection.

Advantages of LINQ to SQL

� Easier than �ADO.NET�.

� Converts data into collection; so we can write the loops easily.
LINQ to SQL - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �LinqToSqlExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �LinqToSqlExample�.
� Click on OK.

Creating �DBML� file:

� Open Solution Explorer.

� Right click on the project (LinqToSqlExample) and click on �Add� � �New
Item� � �Data� � �LINQ to SQL Classes�.
� Type the name as �DataClasses1.dbml� (Database Markup Language).
� Click on �Add�.
� Go to �View� menu � �Server Explorer�.
� Right click on �Data Connections� and click on �Add Connection�.
� Type the server name as �localhost�.
� Select the authentication as �Windows Authentication�.
� Select the database name as �company�.
� Click on OK.
� Expand �company.dbo� � �Tables� � �Employees�.
� Drag and drop �Employees� table from Server Explorer into �Object
Relational Designer� of �DataClasses1.dbml� file.
� It generate two classes called �DataClasses1DataContext� and �Employee�.
� Go to �Build� menu � �Build Solution�.

Program.cs

using System;

using System.Collections.Generic;

using System.Linq;

namespace LinqToSqlExample

class Program

static void Main()

//create reference variables

DataClasses1DataContext db;

//create objects

db = new DataClasses1DataContext();
 //LINQ query

List<Employee> emps = db.Employees.ToList();

//read data row-by-row

for (int i = 0; i < emps.Count; i++)

Employee emp = emps[i];

Console.WriteLine(emp.EmpID + ", " + emp.EmpName + ", " +

emp.Salary);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
C#.NET � Console � Entity
Framework
ADO.NET Entity Framework

ADO.NET Entity Framework (EF)

� �ADO.NET Entity Framework (EF)� is a framework, which is a part of �.NET�,

which is advanced than �ADO.NET�. It was introduced in .NET 4.0.
� �ADO.NET EF� works based on �Ado.NET�.
� �ADO.NET EF� is a database technology, which is used to connect and
interact with databases.

Advantages of Entity Framework

� �Entity Framework� is easier than �ADO.NET�.

� �Entity Framework� automatically converts data into collection; so that it
will be easy to read and manipulate the data.
� �Entity Framework� is better compatible with other frameworks such as
�WPF� and �ASP.NET MVC� etc.

Features of Entity Framework

1. Tables become �model classes�; columns become �properties�.

-
�EmpID� column . �EmpID� property
-
�EmpName� column . �EmpName� property
-
�Salary� column . �Salary� property.
o EmpID: 1, EmpName: Scott, Salary: 4000 . Object
o A group of objects of model class, is treated as a �collection�.
o We will read data from collection; not from the dataset / data reader.
o ADO.NET EF internally and automatically copy the data from
�resultset� to �collection�.

�Employees� table . �Employee� class

2. Every record (row) become �object�.

3. Every �group of objects� is a collection:
4. We can write presentation logic / business logic based on the collections:
Steps for development of Entity Framework

1. Install �EntityFramework� package:

o We have to install �EntityFramework� NuGet package in order to use
Entity Framework.
o A NuGet package is a collection of one or more assemblies. When we
install a NuGet package, all of its assemblies will be added as
reference to the project.
o The �EntityFramework� NuGet package contains an assembly called
�EntityFramework.dll�, which contains all the pre-defined classes of
Entity Framework.
o To install the �EntityFramework� package, use the following
command in �Package Manager Console�.

Install-package EntityFramework

2. Create a model class:

class modelclassname

public datatype property1 { get; set; }

public datatype property2 { get; set; }

}
3. Create a child class for �DbContext� class:

DbContext = Group of DbSet�s

DbSet = a collection of one table

class childclassname : System.Data.Entity.DbContext

public DbSet<modelclass> collectionname { get; set; }

public DbSet<modelclass> collectionname { get; set; }

4. Create an object for the child class:

Childclassname referencevariable ;

referencevariable = new Childclassname();

5. Access the collection:

Referencevariable.collectionname
Entity Framework - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EntityFrameworkExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EntityFrameworkExample�.
� Click on OK.

Installing �EntityFramework� NuGet Package

� Go to �Tools� menu � �NuGet Package Manager� - �Package Manager

Console�.
� Type the command and press Enter.

Install-package EntityFramework
Adding �ConnectionString� in �App.Config�:

� Go to �App.Config� (If exists already).

� Scroll down to end of �App.Config� file and add �ConnectionStrings� as
follows:

<connectionStrings>

<add name="CompanyDbContext"
connectionString="data source=localhost; integrated
security=yes; initial catalog=company"
providerName="System.Data.SqlClient" />

</connectionStrings>
Program.cs

using System;

using System.ComponentModel.DataAnnotations;

using System.Data.Entity;

using System.Collections.Generic;

using System.Linq;

namespace EntityFrameworkExample

public class Employee

[Key]

public int EmpID { get; set; }

public string EmpName { get; set; }

public decimal Salary { get; set; }

public class CompanyDbContext : DbContext

public DbSet<Employee> Employees { get; set; }

class Program

static void Main()

//create reference variable

CompanyDbContext db;

//create object
db = new CompanyDbContext();

//LINQ query

//List<Employee> emps = db.Employees.ToList();

 //List<Employee> emps = db.Employees.Where(temp => temp.Salary
>= 2000).ToList();

List<Employee> emps = db.Employees.OrderBy(temp =>

temp.Salary).ToList();

//read data row-by-row

for (int i = 0; i < emps.Count; i++)

Employee emp = emps[i];

Console.WriteLine(emp.EmpID + ", " + emp.EmpName + ", " +

emp.Salary);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
Entity Framework � FirstOrDefault -
Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �FirstOrDefaultExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FirstOrDefaultExample�.
� Click on OK.

Installing �EntityFramework� NuGet Package

� Go to �Tools� menu � �NuGet Package Manager� - �Package Manager

Console�.
� Type the command and press Enter.

Install-package EntityFramework
Adding �ConnectionString� in �App.Config�:

� Go to �App.Config� (If exists already).

� Scroll down to end of �App.Config� file and add �ConnectionStrings� as
follows:

<connectionStrings>

<add name="CompanyDbContext" connectionString="data

source=localhost; integrated security=yes; initial
catalog=company" providerName="System.Data.SqlClient" />

</connectionStrings>
Program.cs

using System;

using System.ComponentModel.DataAnnotations;

using System.Data.Entity;

using System.Collections.Generic;

using System.Linq;

namespace FirstOrDefaultExample

public class Employee

[Key]

public int EmpID { get; set; }

public string EmpName { get; set; }

public decimal Salary { get; set; }

public class CompanyDbContext : DbContext

public DbSet<Employee> Employees { get; set; }

class Program

static void Main()

//create reference variables

CompanyDbContext db;
//create objects

db = new CompanyDbContext();

//LINQ query: Get single record

 Employee emp = db.Employees.Where(temp => temp.EmpID ==
1).FirstOrDefault();

//read data row-by-row

Console.WriteLine("Emp ID: " + emp.EmpID);

Console.WriteLine("Emp Name: " + emp.EmpName);

Console.WriteLine("Salary: " + emp.Salary);

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Note: If any database connection problem, it shows exception (run

time error).
Entity Framework � Insertion - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EfInsertionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EfInsertionExample�.
� Click on OK.

Installing �EntityFramework� NuGet Package

� Go to �Tools� menu � �NuGet Package Manager� - �Package Manager

Console�.
� Type the command and press Enter.

Install-package EntityFramework
Adding �ConnectionString� in �App.Config�:

� Go to �App.Config� (If exists already).

� Scroll down to end of �App.Config� file and add �ConnectionStrings� as
follows:

<connectionStrings>

<add name="CompanyDbContext" connectionString="data

source=localhost; integrated security=yes; initial
catalog=company" providerName="System.Data.SqlClient" />

</connectionStrings>
Program.cs

using System;

using System.ComponentModel.DataAnnotations;

using System.ComponentModel.DataAnnotations.Schema;

using System.Data.Entity;

using System.Collections.Generic;

using System.Linq;

namespace EfInsertionExample

public class Employee

[Key]

[DatabaseGenerated(DatabaseGeneratedOption.None)]

public int EmpID { get; set; }

public string EmpName { get; set; }

public decimal Salary { get; set; }

public class CompanyDbContext : DbContext

public DbSet<Employee> Employees { get; set; }

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

 decimal sal = Convert.ToDecimal(Console.ReadLine());

//insertion

CompanyDbContext db = new CompanyDbContext();

Employee emp = new Employee();

emp.EmpID = empId;

emp.EmpName = empName;

emp.Salary = sal;

db.Employees.Add(emp);

db.SaveChanges();

Console.WriteLine("Inserted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Entity Framework � Updation - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EfUpdationExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EfUpdationExample�.
� Click on OK.

Installing �EntityFramework� NuGet Package

� Go to �Tools� menu � �NuGet Package Manager� - �Package Manager

Console�.
� Type the command and press Enter.

Install-package EntityFramework
Adding �ConnectionString� in �App.Config�:

� Go to �App.Config� (If exists already).

� Scroll down to end of �App.Config� file and add �ConnectionStrings� as
follows:

<connectionStrings>

<add name="CompanyDbContext" connectionString="data

source=localhost; integrated security=yes; initial
catalog=company" providerName="System.Data.SqlClient" />

</connectionStrings>
Program.cs

using System;

using System.ComponentModel.DataAnnotations;

using System.Data.Entity;

using System.Collections.Generic;

using System.Linq;

namespace EfUpdationExample

public class Employee

[Key]

public int EmpID { get; set; }

public string EmpName { get; set; }

public decimal Salary { get; set; }

public class CompanyDbContext : DbContext

public DbSet<Employee> Employees { get; set; }

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter EmpName: ");

string empName = Console.ReadLine();

Console.Write("Enter Salary: ");

decimal sal = Convert.ToDecimal(Console.ReadLine());

 //updation

CompanyDbContext db = new CompanyDbContext();

Employee emp = db.Employees.Where(temp => temp.EmpID ==

empId).FirstOrDefault();

emp.EmpName = empName;

emp.Salary = sal;

db.SaveChanges();

Console.WriteLine("Updated");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Entity Framework � Deletion - Example

Creating Database

� Note: Ignore this step, if you have created �company� database already.
� Open SQL Server Management Studio. Click on �Connect�.
� Click on �New Query�.
� Type the following code:

create database company

go

use company

go

create table Employees(

EmpID int primary key,

EmpName nvarchar(max),

Salary decimal)

go

insert into Employees values(1, 'Scott', 4000)

insert into Employees values(2, 'Allen', 5000)

insert into Employees values(3, 'Jones', 6000)

go

� Click on �Execute� button. It shows �Query executed successfully� in the

status bar.
Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Console Application�.
� Type the project name as �EfDeletionExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �EfDeletionExample�.
� Click on OK.

Installing �EntityFramework� NuGet Package

� Go to �Tools� menu � �NuGet Package Manager� - �Package Manager

Console�.
� Type the command and press Enter.

Install-package EntityFramework
Adding �ConnectionString� in �App.Config�:

� Go to �App.Config� (If exists already).

� Scroll down to end of �App.Config� file and add �ConnectionStrings� as
follows:

<connectionStrings>

<add name="CompanyDbContext" connectionString="data

source=localhost; integrated security=yes; initial
catalog=company" providerName="System.Data.SqlClient" />

</connectionStrings>
Program.cs

using System;

using System.ComponentModel.DataAnnotations;

using System.Data.Entity;

using System.Collections.Generic;

using System.Linq;

namespace EfDeletionExample

public class Employee

[Key]

public int EmpID { get; set; }

public string EmpName { get; set; }

public decimal Salary { get; set; }

public class CompanyDbContext : DbContext

public DbSet<Employee> Employees { get; set; }

class Program

static void Main()

//accept values from keyboard

Console.Write("Enter Existing EmpID: ");

int empId = Convert.ToInt32(Console.ReadLine());

 //deletion

CompanyDbContext db = new CompanyDbContext();

Employee emp = db.Employees.Where(temp => temp.EmpID ==

empId).FirstOrDefault();
 db.Employees.Remove(emp);

db.SaveChanges();

Console.WriteLine("Deleted");

Console.ReadKey();

Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
C#.NET � Windows Forms
Applications
Introduction to Windows Forms Applications
in C#.NET

Overview of Windows Forms Applications

� �Windows forms applications� are �GUI (Graphical User Interface)� based

applications that can be developed in .NET.
� Windows forms applications are also called as �WinForms�.
� Windows forms applications are created using c#.net.
� Windows forms applications are user-friendly and easy to use.
� Windows forms applications are created based on Object-oriented
programming concepts.
� Windows forms application is a collection of windows forms.
� A windows form (win form) is a GUI container and a window that contains UI
(user interface), using which the user can interact with the system. Ex: Login
form
� Windows forms applications can interact with databases using ADO.NET.
� Windows forms applications support �local GUI� that runs on windows
operating system locally.
� Windows forms applications are compiled into �.exe� file.
o The exe file is also called as �assembly�.
o The exe file contains compiled source code (in MSIL (Microsoft
Intermediate Language)) of windows forms application.

Ex: WindowsFormsApplication1.exe
Assemblies (dll files) to develop windows forms applications:

� .NET provides the following assemblies (dll files) to develop windows forms
applications:
1. System.Windows.Forms.dll
2. System.Drawing.dll

System.Windows.Forms.dll

. �System.Windows.Forms.dll� assembly
� �System.Windows.Forms� namespace
o �Form� class
o �Label� class
o �Button� class
o �TextBox� class

etc.
The �System.Windows.Forms.Form� class

System.Windows.Forms.Form

� �Form� is a class, which is a member of �System.Windows.Forms� is a

namespace.
� The object of �Form� class represents a form.
� Every form contains basic look and feel such as title bar, minimize box,
maximize box, close box etc.
Programming Model of Windows Form in
C#.NET

Programming Model of a Windows Form

� To create a form, you have to create a child class for

�System.Windows.Forms.Form� class & you have to create an object for the
child class.
� The child class can be �public� class optionally.
� The child class must inherit from �System.Windows.Forms.Form� class. The
�System.Windows.Forms.Form� class provides the layout (appearance),
properties, events and methods for the child class.

Syntax:

public partial class Classname : System.Windows.Forms.Form

public Classname ()

InitializeComponent();

� The child class must be �partial class�.

o The visual studio generated designer code (Form1.Designer.cs) and
user-defined code (Form1.cs) should be combined as a single class at
compile-time. To make this possible, the form class must be �partial
class�.
� �public Classname()�
o It is the constructor that executes as soon as an object for the form
class is created at run time.

� InitializeComponent()
o The InitializeCompoent() method initializes the basic look and feel of
the form. The definition of InitializeCompoent() method is generated
in �Form1.Designer.cs� file.

� Program.cs
o In Program.cs, at main method, the following statement will create an
object for the form class.

Application.Run(new ChildClassname ());

Windows Forms Application � First Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�. Select �Visual C#�.
� Select �Windows Forms Application�.
� Type the project name as �WindowsFormsApplication1�.
� Type the location as �C:\CSharp�.
� Type the solution name as �WindowsFormsApplication1�.
� Click on OK.
� Right click on the form and click on �View Code�.

Form1.cs

using System;

using System.Windows.Forms;

namespace WindowsFormsApplication1

public partial class Form1 : Form

public Form1()

InitializeComponent();

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output
Form Constructor - Example

Creating Project

� Open Visual Studio 2015.

� Go to �File� � �New� � �Project�.
� Select �.NET Framework 4.6�.
� Select �Visual C#�.
� Select �Windows Forms Application�.
� Type the project name as �FormConstructorExample�.
� Type the location as �C:\CSharp�.
� Type the solution name as �FormConstructorExample�.
� Click on OK.
� Right click on the form and click on �View Code�.

Form1.cs

using System;

using System.Windows.Forms;

namespace FormConstructorExample

public partial class Form1 : Form

public Form1()

InitializeComponent();

MessageBox.Show("Message from Form1 Constructor");

}
Running the Project

� Go to �Debug� menu and click on �Start Debugging�.

Output

Click on OK
Properties of
�System.Windows.Forms.Form� class

Properties of �System.Windows.Forms.Form� class

� The properties of �System.Windows.Forms.Form� class provides a set of

properties to customize the look and feel of the form.

Sl.
No

Property

Description

Text

Represents title of the form that appears in the titlebar

of the form.

Syntax: this.Text = "title here";

ShowIcon

Shows / hides the form icon.

True: Shows the form icon.

False: Hides the form icon.