Salvi College

Written By

Prof. Sonu Raj

TYBsc-IT
Semester-V

Subject-Advanced Web Programming

1 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
Syllabus
Introducing .NET
Unit-I ​
Web ​ Form ​
C# Language Types, Objects, and Namespaces ​Unit-II ​ Form ​ Controls
Fundamentals

Unit-III
Error Handling, Logging, and Tracing State Management Styles, Themes, and Master
Pages
Unit-IV
ADO.NET Fundamentals Data Binding The Data Controls
XML
Unit-V ​
Security Fundamentals ASP.NET AJAX
Index
Sr. No Topic Page No
1
3-40 ​ Web Form
Introducing .NET C# Language Types, Objects, and Namespaces ​ 2​
Fundamentals
 41-61 ​ Error Handling, Logging, and Tracing
Form Controls ​ 3​

62-79
State Management Styles, Themes, and Master Pages ​
4
80-91
ADO.NET Fundamentals Data Binding The Data Controls ​
XML ​
5 ​Security Fundamentals
ASP.NET AJAX
92-107
2 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Unit-I
Topics:

.Net Framework | C# Language |Types,

 Objects, and Namespaces

3 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Q1. What is .NET Framework? Explain its architecture with help of
diagram.
.NET Framework is a platform created by Microsoft for building, deploying, and running applications
and services that use .NET technologies, such as desktop applications and Web services.

▪ It is a platform for application developers.

▪ It is a Framework that supports Multiple Language and Cross language
integration.
▪ It has IDE (Integrated Development Environment).
▪ Framework is a set of utilities or can say building blocks of our application
system.
▪ .NET Framework provides interoperability between languages i.e. Common Type System
(CTS).
▪ .NET Framework also includes the .NET Common Language Runtime (CLR), which responsible for
maintaining the execution of all applications developed using the .NET library.
▪ The .NET Framework consists primarily of a gigantic library of
code.

Components of the .Net

Framework:

User Interface and Program: ​We can create various type of

application using .net framework such as Console Application
Windows Application Web application

Base class
 Library:
▪ Base class library is one of component of .Net Framework. It supplies a library of base classes that
we can use to implement applications quickly.

CLR (Common Language

Runtime)
▪ Common Language Runtime (CLR) is the programming (Virtual Machine component) that
manages the execution of programs written in any language that uses the .NET Framework, for
example C#, VB.Net, F# and so on.

▪ We can say that it is heart and soul of .Net Framework or

backbone.

Q2. Explain CLR in

detail.

▪ Common Language Runtime (CLR) is the programming (Virtual Machine component) that
manages the execution of programs written in any language that uses the .NET Framework, for
example C#, VB.Net, F# and so on.

4 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ We can say that it is heart and soul of .Net Framework or
backbone.

▪ Programmers write code in any language, including VB.Net, C# and F# then they compile their
programs into an intermediate form of code called CLI in a portable execution file (PE) that can be
managed and used by the CLR and then the CLR converts it into machine code to be will executed
by the processor.

▪ The information about the environment, programming language, its version and what class libraries
will be used for this code are stored in the form of metadata with the compiler that tells the CLR how
to handle this code.

▪ The CLR allows an instance of a class written in one language to call a method of the class written
in another language.
 Components of the
CLR:

CTS ​Common Type System (CTS) describes a set of types that can be used in different .Net
languages in common. That is, the Common Type System (CTS) ensure that objects written in
different .Net languages can interact with each other. For Communicating between programs
written in any .NET complaint language, the types must be compatible on the basic level. These
types can be Value Types or Reference Types. The Value Types are passed by values and
stored in the stack. The Reference Types are passed by references and stored in the heap.

CLS ​CLS stands for Common Language Specification and it is a subset of CTS. It defines a set
of rules and restrictions that every language must follow which runs under .NET framework. The
languages which follow these set of rules are said to be CLS Compliant. In simple words, CLS
enables cross-language integration or Interoperability.

For Example ​if we take C-Sharp and VB.net in C# each statement must have to end with a
semicolon it is also called a statement Terminator but in VB.NET each statement should not end
with a semicolon (;). So, these syntax rules which we have to follow from language to language
differ but CLR can understand all the language Syntax because in.NET each language is
converted into MSIL code after compilation and the MSIL code is language specification of CLR.

MSIL

5 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

It is language independent code. When you compile code that uses the .NET Framework library,
 we don't immediately create operating system - specific native code.

Instead, we compile our code into Microsoft Intermediate Language (MSIL) code. The MSIL
code is not specific to any operating system or to any language.

Advantages -
• ​MSIL provide language interoperability as code in any .net language is compiled on
MSIL
• ​Same performance in all .net languages
• ​support for different runtime environments
• ​JIT
compiler in CLR converts MSIL code into native machine code which is executed
by OS

Functions of the
CLR

o Garbage Collector o Exception handling o Type

safety o Memory management (using the Garbage
Collector) o Security o Improved performance

Q3. What is namespace? How to create namespace and

alias?

A namespace is designed for providing a way to keep one set of names separate from
another. The class names declared in one namespace does not conflict with the same class
names declared in another.

Defining a
Namespace

A namespace definition begins with the keyword namespace followed by the namespace
name as follows:

namespace
 namespace_name {
// code
declarations }

Example:
using System;
namespace first_space

{ ​class namespace_cl {​

public void func()

{ Console.WriteLine("Inside
first_space");
}

6 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

} } ​namespace

second_space {​ ​class

namespace_cl {​ ​public

void func()
{ Console.WriteLine("Inside
second_space");

} } } ​class TestClass {​

static void Main(string[] args)

{ first_space.namespace_cl fc = new
first_space.namespace_cl(); second_space.namespace_cl sc =
new second_space.namespace_cl(); fc.func(); sc.func();
Console.ReadKey();

} } ​The using

Keyword
The using keyword states that the program is using the names in the given namespace. For
example, we are using the System namespace in our programs. The class Console is defined
 there. We just write:

Console.WriteLine ("Hello there");

We could have written the fully qualified name

as:

System.Console.WriteLine("Hello
there");

Alias of
Namespace:

using A=System.Console;

class Test { ​static void

Main() {​ ​A.Write("Craetion of

Alias"); A.ReadKey();
​
}
}

Q4. Explain different types of data types in

C#.
OR Explain primitive and non-primitive data
types in C#

7 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

The data types in C# are categorized into the following
types:

▪ ​Value types
▪ ​Reference types
▪ ​Pointer types

Value Type

Value type variables can be assigned a value directly. They are derived from the class
System.ValueType.
The value types directly contain data. Some examples are int, char, and float, which stores
numbers, alphabets, and floating-point numbers, respectively. When you declare an int type, the
system allocates memory to store the value.

Reference Type

The reference types do not contain the actual data stored in a variable, but they contain a
reference to the variables.

In other words, they refer to a memory location. Using multiple variables, the reference types
can refer to a memory location. If the data in the memory location is changed by one of the
variables, the other variable automatically reflects this change in value. Example of built-in
reference types are: object, dynamic, and string.
 8 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
Q5. Explain the implicit and explicit conversion of data types with
examples.

▪ The process of converting from one data type to another data type is called
conversion.

▪ Conversion can be 2 types as follows:

▪ When one type of data is assigned to another type of variable, an implicit type conversion will take
place automatically if

o The two types are compatible. o The destination type has a range
that is greater than the source type.

▪ When these two conditions are met, a widening conversion takes place. For example, the int type
is always large enough to hold all valid byte values, and both int and byte are compatible integer
types, so an implicit conversion can be applied.

▪ For widening conversions, the numeric types, including integer and floating-point types, are
compatible with each other.

▪ For example, the following program is perfectly valid since long to double is a widening conversion
that is automatically performed.

using System; class LtoD { static void Main() { ​long L; double

​ D; L = 100123285L; D = L;

Console.WriteLine("L and D: " + L + " " + D); } ​} ​Casting Incompatible Types Although
​ the
implicit type conversions are helpful, they will not fulfil all programming needs because they apply
only to widening conversions between compatible types. For all other cases we must employ a
cast. A cast is an instruction to the compiler to convert the outcome of an expression into a
specified type. Thus, it requests an explicit type conversion. ​A cast has this general form:

(target-type) expression

Here, target-type specifies the desired type to convert the specified expression to.
For ​Example

double x, y; if you want the type of the expression x/y to be int,

you can write

9 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

 (int) (x / y)

Here, even though x and y are of type double, the cast converts the outcome of the expression to
int. The parentheses surrounding x / y are necessary. Otherwise, the cast to Int would apply only
to the x and not to the outcome of the division.

The cast is necessary here because there is no implicit conversion from double to int. When a
cast involves a narrowing conversion, information might be lost.

Q6. Explain Boxing and Unboxing with reference to value type and
reference type.

Boxing​: Any type, value or reference can be assigned to an object without explicit conversion.
When a compiler fined a value where it needs a reference type, it creates an object ‘box’ into
which it places the value of the value type.

Example: -

int m = 10; object om = m; When executed, this code creates a temporary reference _type ‘box’
for the object on heap. We can also use a C-style cast for boxing.

int m = 10; object om =

(object) m;

Note that the boxing operation creates a copy of the value of the m integer to the object om.
Both the variables exist but the value of om resides on the heap. This means that the values are
independent of each other.

Example

int m =10; object om = m; m = 20;

Console.WriteLine(m); // m= 20
Console .WriteLine(om); //om=10

Unboxing​:

Unboxing is the process of converting the object type back to the value type. Remember that a
variable can be unboxed only if it has been previously boxed. In contrast to boxing, unboxing is
an explicit operation.

Example:-

int m = 100; object om = m;

//boxing int n = (int) om;
//unboxing
 When performing unboxing, C# checks the value type we request is actually stored in the object
under conversion. Only if it is, the value is unboxed.

Q7. List and explain the comparison and logical operators

in C#.

Comparison operators​: It is also called as relational operator. They are used to

compare at least two operands. Below is the list of relational operators as follows:

10 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Logical operators ​Logical operators are used to combine two or more condition. Below is list of
logical operators used in C#.

Q8. Explain flow control, explain what is break and continue

statement

The statements inside your source files are generally executed from top to bottom, in the order
that they appear. Control flow statements, however, break up the flow of execution by employing
decision making, looping, and branching, enabling your program to conditionally execute
particular blocks of code.

Break Statement

The break statement is used to exit from loops and switch statements. The break statement
terminates the execution control from a loop or a switch statement to the next statement after the
loop or switch statement.
 The general format is:

Example:-Write a program to generate the following

triangle 1 ​1 2 1
​ 23

using System; class

demo { ​public static void

Main() {​ ​for(int

i=1;i<=5;i++) {​ ​for(int

j=1;j<=5;j++) {​

Console.Write(" "+j);
if(j==i) { ​break; }

11 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

} ​Console.WriteLine(" ");

} ​} } ​Continue

Statement

The continue statement causes early iteration of a loop. It skips the remaining statements
after the continue statement and moves the execution control to the next iteration of the loop.

The general format is:

using System; class demo { ​public static void Main() {​ ​for(int i=1;i<=25;i++) {​ ​if(i%2!=0) {​

continue; }​ ​else Console.Write("

​ "+i); } ​} } Use the break keyword to stop the loop and

the continue keyword to skip one loop cycle and continue

​ to the next.

using System;

public class Program { ​public static void Main() {​

 Console.WriteLine("Demonstrating the use of break.\n"); for
​
(int x = 1; x < 10; x++) { ​if (x == 5) break;
​
Console.WriteLine("Number " + x); }

Console.WriteLine("\nDemonstrating the use of

​ (int x = 1; x < 7; x++) { ​if (x == 5) continue;

continue.\n"); for ​
Console.WriteLine("Number " + x); } ​}

12 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

} ​Demonstrating the use of

break.
Number 1 Number 2 Number 3
Number 4 Demonstrating the use
of continue. Number 1

Number 2 Number 3 Number 4 Number 6 ​Q9. Give general

form of switch statement. Explain with example.

▪ The switch statement is similar to if statement in that it executes code conditionally based on the
value of a test. However, switch enables us to test for multiple values of a test variable in one go,
rather than just a single condition.

▪ This test is limited to discrete values, rather than clauses such as ‘‘greater than X,’’ so its use is
slightly different; but it can be a powerful technique.

▪ The basic structure of a switch statement is as

follows:

switch (<testVar>) { ​case<comparisonVal1>: <code

​
to execute if <testVar> == <comparisonVal1>>
break; case<comparisonVal2>: <code to execute if
<testVar> == <comparisonVal2>> break; . . .
case<comparisonValN>: <code to execute if
<testVar> == <comparisonValN>> break; default:
<code to execute if <testVar> != comparisonVals>
 break; } ​Example:

class SwitchEg { ​static void Main(string[]

args) {​ ​const string myName = "karli";

const string sexyName = "angelina";
const string sillyName = "ploppy"; string
name; Console.WriteLine("What is your
name?"); name = Console.ReadLine();
switch (name.ToLower())

13 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

{ ​case myName: Console.WriteLine("You

​ have the
same name as me!"); break; case sexyName:

Console.WriteLine("My, what a sexy name you

have!"); break; case sillyName:
Console.WriteLine("That’s a very silly name."); break;

} ​Console.WriteLine("Hello {0}!", name);

Console.ReadKey(); } ​} Q10.
​ Give syntax of foreach
loop. Explain with example.

A foreach loop mostly used with array and collection such ArrayList. A foreach loop enables
us to address each element in an array using this simple syntax:

foreach (<baseType><name> in <array>) { ​// can use <name> for each element }​ ​This loop will

cycle through each element, placing it in the variable <name> in turn, without danger of
accessing illegal elements. We don’t have to worry about how many elements are in the array,
and we can be sure that we get to use each one in the loop.

The main difference between using this method and a standard for loop is that foreach gives us
read- only access to the array contents, so we can’t change the values of any of the elements.

Example ​using System; class Abc static void Main(string[] args) { ​string[]

friendNames = { "Robert Barwell", "Mike Parry", "Jeremy Beacock" };

 Console.WriteLine("Here are {0} of my friends:", friendNames.Length);
foreach (string friendName in friendNames) {

Console.WriteLine(friendName); }​ ​Console.ReadKey(); }​

Q11. Difference between for and foreach

loop

Afor loop executes a statement or a block of statements repeatedly until a specified expression
evaluates to false. There is need to specify the loop bounds (minimum or maximum).

Example:
int j = 0;

14 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

for (int i = 1; i <= 5; i++) { ​j= j + i ; }​ ​The foreach statement repeats a group of embedded

statements for each element in an array or an object

​ collection. You do not need to specify the
loop bounds minimum or maximum.

Example: ​int j = 0; int[] tempArr = new int[] {

0, 1, 2, 3, 5, 8, 13 }; foreach (int i in tempArr

) { ​j = j + i ; }​

Q12. Explain variable sized array with suitable

example.

OR
Explain jagged array with
example.

Jagged array is also called Array of Array or variable sized array. In a jagged array, each row
may have different number of columns.

It is equivalent to an array of variable sized one-dimensional arrays. The Length property is

used to get the length of each one-dimensional array.
 A jagged array can be declared and initialized as
follows:

datatype[][] arrayname=new datatype[rowsize][];

arrayname[0]=new datatype[]{val1,val2,val3, ...};
arrayname[1]=new datatype[]{val1,val2,val3, ...};
arrayname[2]=new datatype[]{val1,val2,val3, ...};

Example

class numadd { ​public

static void Main() {​ ​int[][]

x=new int[4][]; x[0]=new

​
int[2]{5,13};

15 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

x[1]=new int[3]{7,8,11};
x[2]=new int[4]{2,3,4,5};
x[3]=new int[1]{9}; for(int

i=0;i<4;i++) { ​for(int

j=0;j<x[i].Length;j++) {​

Console.Write(x[i][j]+"\t"); }​

Console.Write("\n");
 } ​}

Q13. Explain ref parameter and out

parameter

Reference Parameter:

It is used as a call by reference in C#. It is used in both places; when we declare a method and
when we call the method. In this example we create a function (cube) and pass a ref parameter
in it, now we look at the value before we call the function and after we call the function.

classAbc { ​public void cube(ref int x) {​ ​x= x * x * x; }​ ​} class Program {​ ​static void

Main(string[] args) {​ T ryRef tr = new TryRef(); int y = 5; Console.WriteLine("The

value of y before the function call: " + y); tr.cube(ref y); Console.WriteLine("The

value of y after the function call: " + y); Console.ReadLine(); } ​} ​Output

Parameter:
Sometimes we do not want to give an initial value to the parameter; in this case we use the out
parameter. The declaration of the out parameter is the same as the ref parameter. But it is used
to pass the value out of a method. Now we look at the

classAbc

16 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

{ ​public int mul(int a, out int b) {​ ​b = a *

a; return
​ b; } ​} class Program {​ ​static

void Main(string[] args) {​ ​tryout to =

new tryout(); int

​ x,y; x = to.mul(10, out
y); Console.WriteLine("The output is:
"+x);

Console.ReadLine();

} ​}
Q14. Is Multiple Main () allowed in C#?
Justify
We can use more than on Main Method in C# program, But there will only one Main Method
which will act as entry point for the program.

using System; class A { ​static void

Main(string[] args) {​

Console.WriteLine("I am from Class

A"); Console.ReadLine();
​ } ​} class B {​

static void Main(string[] args) {​

Console.WriteLine("I am from Class

B"); Console.ReadLine();
​ } ​} Try to

execute Program as given below:

csc filename.cs /main:classname As in given program there are two classes A and B in which
each containing A Main Method. We may write as.

17 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

csc filename.cs /main:A [ for Class A Main Execution ] or, csc filename.cs /main:B [ for
Class B Main Execution ]
Q15. Difference between Structures and Classes.
Structure Class ​It is value type It is reference type. Structure stored in stack memory.
Class stored in heap memory. Does not consist of parametrized constructor.
Consist of parametrized constructor.
Does not allow inheritance. Allow inheritance. Does not consist of destructor. Consist of
destructor. Structure created with help of struct keyword.

Classes created with the help of class keyword. Example:- struct Book { ​}
 Example:- class Abc { ​}
Q16. Need of enumerator data type in C#
▪ An enum is a value type with a set of related named constants often referred to as an
enumerator list.
▪ The enum keyword is used to declare an enumeration. It is a primitive data type, which
is user defined.
▪ Enums type can be integer (float, int, byte, double etc.). But if you used beside int it
has to be cast.
▪ The keyword enum is used to create numeric constants in .NET framework.
▪ There must be a numeric value for each enum type.
▪ The default underlying type of the enumeration elements is int. By default, the first
enumerator has the value 0, and the value of each successive enumerator is increased
by 1.
Example:-
using System; ​enumDays {Sat, Sun, Mon, Tue, Wed, Thu, Fri};
class Abc { ​public static void main() {​ Console.WriteLine((int)Days.Wed);
​

Console.WriteLine((Days)4); } ​}
Q17. Explain inheritance and polymorphism.
Inheritance ​Inheritance is the concept we use to build new classes using the existing
class definitions. Through inheritance we can modify a class the way we want to create
new objects. The original class is known as base or parent class & the modified class is
known as derived or subclass or child class. The
18 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
concept of inheritance facilitates the reusability of existing code & thus improves the integrity of
programs & productivity of programmers.

Polymorphism ​Polymorphism is the ability to take more than one form. For example, an
operation may exhibit different behavior in different situations. The behavior depends upon the
types of data used on the operation. Polymorphism is extensively used while implementing
inheritance.

Two types ​Compile time

polymorphism Runtime time
polymorphism

Q18. What are sealed classes and sealed methods? Why are
they used?
The methods declared with a sealed keyword in its header are known as sealed methods. Such
 method provides a complete implementation to its base class virtual method using the override
keyword.

Characteristics

▪ A method cannot be defined as sealed unless that method is an override of a method in its base
class.
▪ A sealed method cannot be overridden further.
▪ Sealed methods are useful to avoid problems caused by overriding the existing
functionality.
▪ It prevents the user from changing the internal functionality of a
class.

Example:

using System; class A { ​public

virtual void F() {​

Console.WriteLine("A.F"); }​

public virtual void G() {​

Console.WriteLine("A.G"); }​ ​}

class B: A {​ ​sealed override

public void F() {​

Console.WriteLine("B.F"); }​

override public void G() {​

Console.WriteLine("B.G"); }​ ​}

class C: B

19 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

{ ​override public void G() {​ ​Console.WriteLine("C.G"); }​ ​} ​The class B provides two override

methods: an F method that has the sealed modifier and a G method

​ that does not. B's use of the
sealed modifier prevents C from further overriding F.
 Sealed
Classes:

▪ Generally if we create classes we can inherit the properties of that created class in any class
without having any restrictions.
▪ In some situation we will get requirement like we don’t want to give permission for the users to
derive the classes from it or don’t allow users to inherit the properties from particular class.
▪ For that purpose we have keyword called “sealed” in
OOPS.
▪ When we defined class with keyword “Sealed” then we don’t have a chance to derive that
particular class and we don’t have permission to inherit the properties from that particular class.
▪ A sealed class cannot be inherited.
▪ It is an error to use a sealed class as a base
class.
▪ Use the sealed modifier in a class declaration to prevent inheritance of the
class.
▪ It is not permitted to use the abstract modifier with a sealed
class.

Example:

using System;

sealed class MyClass { ​public int x; public

​ int y;

} ​class MainClass {​ ​public static void Main() {​

MyClass mC = new MyClass(); mC.x

​ = 110;
mC.y = 150; Console.WriteLine("x = {0}, y =

{1}", mC.x, mC.y); } ​}

Q19. What are the rules in defining a constructor? Explain static constructor with
example.

Rules for
constructor:
 ▪ A constructor should have the same name as that of its
class.

20 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ Constructors can take any number of arguments.
▪ Constructor cannot return any value.
▪ A static constructor is used to initialize static variables of a class. It is declared using the static
keyword. A class can have only one static constructor.

Static Constructor:

The general syntax of a static constructor is shown

below.

static classname()
{

//static member initializations; } ​▪ Also note that a static constructor is parameter less and no

access modifiers are allowed with its declaration.

​ The exact timing of static constructor
execution is implementation-dependent, but is subject to the following rules:
▪ The static constructor for a class executes before any instance of the class is
created.
▪ The static constructor for a class executes before any of the static members for the class are
referenced.
▪ The static constructor for a class executes after the static fields initializes for the
class.
▪ The static constructor for a class executes at most one time during a single program
execution.

Example:

class A { ​static A() {​ ​Console.WriteLine("static

constructor A is invoked"); }​ ​public static void

Main() {​ ​} }
Q20. Explain various Types of Constructors
in C#

Default and
Parameterized

▪ When constructor does not accept any parameter then it is referred as default constructor or
zero parametrized.

▪ When constructor accepts the parameter then it is referred as parametrized

constructor.

Example:

using System; class test

{ ​double length, breadth;
public test()

21 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

{ ​Console.WriteLine("default cons"); }​

public test(double l, double b) {​

//Console.WriteLine("paramaterized cons");
length = l; breadth = b; } ​public double

area() {​ ​return (length * breadth);

} ​} class testmain {​ ​public static void Main() {​ ​test

defaultcon =new test();//calls default cons test

​ t1
= new test(10.05, 100.45); double result =
t1.area(); Console.WriteLine("area of

rectangle-->" + result); Console.ReadLine(); } ​}

Private constructor

▪ Private constructors are used to restrict the instantiation of object using ‘new’ operator.
▪ A private constructor is a special instance constructor. It is commonly used in classes that
contain static members only.
▪ This type of constructors is mainly used for creating singleton object.
▪ If you don't want the class to be inherited we declare its constructor private.

Example:

using System; class test { ​private

test() {​ ​Console.WriteLine("private

cons "); }​ ​public test(int x) {​

22 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Console.WriteLine("non private cons--->"+ x); } ​} class testmain {​ ​public

static void Main() {​ ​test t1 = new test();//Error'test.test()' is inaccessible due

to its protection level test

​ t2 = new test(10); Console.ReadLine(); } ​} ​Static

Constructor

▪ There can be only one static constructor in the

class.
▪ The static constructor should be without parameters.
▪ It can only access the static members of the
class.
▪ There should be no access modifier in static constructor
definition.

Example:

using System; class test { ​static int x; static

​
test() { ​Console.WriteLine("static cons "); x​ =
10;//set the values for static member here }

public static void show() {​

 Console.WriteLine("show of x--->" + x); }​ ​}

class testmain {​ ​public static void Main() {​

test.show(); Console.ReadLine();
​ } ​}

23 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Copy constructor

When constructor accepts the object as parameter then it is referred as copy

constructor. ​Example:

using System; class test { ​double length, breadth; public

​ test() {

Console.WriteLine("default cons"); }​ ​public test(double l, double b) {​

//Console.WriteLine("paramaterized cons"); length

​ = l; breadth = b; }

public test(test t1) {​ ​length = t1.length; breadth

​ = t1.breadth; } ​public

double area() {​ ​return (length * breadth); }​ ​} class testmain {​ ​public static

void Main() {​ ​test defaultcon = new test();//calls default cons test

​ t1 = new
test(10,10); double result = t1.area(); Console.WriteLine("area of
rectangle t1-->" + result); test t2 = new test(20, 20); double result1 =
t2.area(); Console.WriteLine("area of rectangle t2-->" + result1); test t3 =
new test(t2); double result_copy = t3.area(); Console.WriteLine("area of
rectangle t3 is copy_con of t2-->" + result_copy); Console.ReadLine(); } ​}

24 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Q21. How multiple inheritance achieved using

interfaces?

C# does not support multiple inheritance. However, you can use interfaces to implement
multiple inheritance. The following program demonstrates this:
 Example:

using System; class Shape

{ ​public void setWidth(int w)

{ ​width = w; }​ ​public void

setHeight(int h) {​ ​height = h;

} ​protected int width; protected

​ int

height; } ​public interface

PaintCost {​ ​int getCost(int area); }​

class Rectangle : Shape,

PaintCost {​ ​public int getArea() {​

return (width * height); }​ ​public int

getCost(int area) {​ ​return area *

70; }​ ​} class RectangleTester {​

static void Main(string[] args) {​

Rectangle Rect = new

Rectangle(); int
​ area;

25 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Rect.setWidth(5); Rect.setHeight(7); area = Rect.getArea();
Console.WriteLine("Total area: {0}", Rect.getArea());
Console.WriteLine("Total paint cost: ${0}" ,

Rect.getCost(area)); Console.ReadKey(); } ​} }

Q22. When is explicit interface

necessary?

▪ C# does not support multiple inheritances, but a class has the option of implementing one or
 more interfaces.
▪ One challenge with interfaces is that they may include methods that have the same signatures as
existing class members or members of other interfaces.
▪ Explicit interface implementations can be used to disambiguate class and interface methods that
would otherwise conflict.
▪ Explicit interfaces can also be used to hide the details of an interface that the class developer
considers private.
▪ To explicitly implement an interface member, just use its fully qualified name in the
declaration.
▪ A fully qualified interface name takes the form
InterfaceName.MemberName

Example:

interface I1 { ​void A(); }​ ​interface

I2 {​ ​void A(); }​ ​class C : I1, I2 {​

public void I1.A() {​

Console.WriteLine("A() from I"); }​

void I2.A() {​

Console.WriteLine("A() from I2");

} ​}

Q23. Explain the similarities and differences between Interfaces and

Abstract classes

Similarities​:

▪ Both abstract classes and interfaces may contain members that can be inherited by a derived
class.

26 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ Neither interfaces nor abstract classes may be directly instantiated, but we can declare variables of
these types. If we do, we can use polymorphism to assign objects that inherit from these types to
variables of these types.
 ▪ In both cases, we can then use the members of these types through these variables, although we
don’t have direct access to the other members of the derived object.

Differences:

▪ Derived classes may only inherit from a single base class, which means that only a single abstract
class can be inherited directly. Conversely, classes can use as many interfaces as they want
▪ Abstract classes may possess both abstract members and non-abstract members. Interface
members conversely, must be implemented on the class that uses the interface they do not possess
code bodies.
▪ Moreover, interface members are by definition public but members of abstract classes may also
be private (as long as they aren’t abstract), protected, internal, or protected internal. In addition,
interfaces can’t contain fields, constructors, destructors, static members, or constants.

Q24. Explain method overriding with

example

▪ Method overriding in C# is achieved through inheritance.

▪ If a class is inherited by a derived class, then the derived class can override the base class
method. This concept is termed as Method Overriding.
▪ Method Overriding is implemented in C# using the keywords virtual and override. The base class
method that has to be overridden must be marked as virtual or abstract (if the base class is an
abstract class).
▪ The derived class method that overrides the base class method should be marked with the
keyword override.

Example:

using System; class A { ​public virtual void Test() {

Console.WriteLine("A::Test()"); } }​ ​class B : A {​ ​public

override void Test() { Console.WriteLine("B::Test()"); } }​

class C : B {​ ​public override void Test() {

Console.WriteLine("C::Test()"); } }​ ​class Program {​ ​static

void Main(string[] args) {​ ​A a = new A(); B

​ b = new B(); C
c = new C();
27 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
a.Test(); // output --> "A::Test()"
b.Test(); // output --> "B::Test()"
c.Test(); // output --> "C::Test()"
a = new B(); a.Test(); // output
--> "B::Test()" b = new C();
b.Test(); // output --> "C::Test()"

Console.ReadKey(); } ​}

Q25. Differentiate Overloading and

Overriding

Overloading ​Method Overloading means having two or more methods with the same name but
with different signature (different parameters list and different type of parameters) in same class
or in different classes. Method Overloading forms compile-time polymorphism.

Overriding ​Method overriding means having two methods with same name and same signature,
one method in base class and other method in derived class.

A subclass inherits methods from a base class. Sometimes, it is necessary for the subclass to
modify the methods defined in the base class. This is referred to as method overriding.

This can be achieved by using the virtual and override keywords. We have to use the virtual
keyword for the method which in base class and override keyword for the method in subclass.

By default functions are not virtual in C# and so you need to write “virtual”
explicitly.
Q26. Explain method hiding with
example.

In a C# program a derived class can have methods with the same signature as that of its base
class methods. This hides the base class methods by its derived class counterparts and gives a
warning.

This warning can be suppressed by using the ​new ​keyword with the derive class methods. This
means that the members of the base class are made intentionally hidden by the members
having the same signature in the derived class. The new function will never be invoked by a
base class pointer.

Example:-

class demo

28 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

{ ​public void disp() {​ ​System.Console.WriteLine("From disp

method of base class"); }​ ​} class test:demo {​ ​new public void

disp() {​ ​System.Console.WriteLine("From disp method of

derived class"); }​ ​public static void Main() {​ ​test t=new test();

t.disp(); } ​}

Q27. What is the difference between overriding methods and hiding

methods?
 Overriding methods:

In method overriding we can override a method in base class by creating similar method in
derived class this can be achieved by using inheritance principle and using “​virtual & override​”
keywords.

If we want to override base class method then we need to declare base class method with
“virtual” keyword and the method which we created in derived class to override base class need
to declare with “override” keyword like as shown below

Example:-

class SampleA { ​public virtual void Show() {​

Console.WriteLine("Sample A Test

Method"); }​ ​} class SampleB:SampleA {​

public override void Show() {​

Console.WriteLine("Sample B Test

Method"); }​ ​} class Program {​ ​static void

Main(string[] args)

29 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

{ ​SampleA a=new

SampleA(); SampleB
​
b=new SampleB();
a.Show(); b.Show(); a =
new SampleB(); a.Show();

Console.ReadLine(); } ​} }

Hiding methods:

To hide base class methods in derived classes we can declare derived class methods with new
keyword. To use new keyword, we need to write the code like as shown below

Example:-
 class SampleA { ​public void Show() {​

Console.WriteLine("Sample A Test

Method"); }​ ​} class SampleB:SampleA {​

public new void Show() {​

Console.WriteLine("Sample B Test

Method"); }​ ​} class Program {​ ​static void

Main(string[] args) {​ ​SampleA a=new

SampleA(); SampleB
​ b=new SampleB();
a.Show(); b.Show(); a = new SampleB();

a.Show(); Console.ReadLine(); } ​}

Q28. Define each of the following

terms:

Derived class ​The functionality of an existing class can be extended by creating a new class
from it. The new class is then called a child class or derived class. The derived class inherits the
properties of the base class.

Abstract class

30 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

An Abstract class is a non-instantiable class which is either partially implemented, or not at all
implemented. It can have abstract methods as well as non-abstract methods. Abstract classes
require subclasses to provide implementations for the abstract methods. It provides default
functionality to its sub classes.

Static class

A static class is class whose objects cannot be created and must contain only static
members.

Sealed class

A sealed class is a class which cannot be inherited. In C#, the sealed modifier is used to define
a class as sealed.
 Partial class

It is possible to split the definition of a class over two or more source files. Each source file
contains a section of the type or meth

Q29. Write a short note on

Assembly.

An assembly in ASP.NET is a collection of single-file or multiple files. The assembly that has
more than one file contains either a dynamic link library (DLL) or an EXE file. The assembly also
contains metadata that is known as assembly manifest.

The assembly manifest contains data about the versioning requirements of the assembly, author
name of the assembly, the security requirements that the assembly requires to run, and the
various files that form part of the assembly.

The biggest advantage of using ASP.NET Assemblies is that developers can create applications
without interfering with other applications on the system. When the developer creates an
application that requires an assembly that assembly will not affect other applications.

The assembly used for one application is not applied to another application. However, one
assembly can be shared with other applications. In this case the assembly has to be placed in the
bin directory of the application that uses it.

This is in contrast to DLL in the past. Earlier developers used to share libraries of code through
DLL. To use the DLL that is developed by another developer for another application, we must
register that DLL in our machine. In ASP.NET, the assembly is created by default whenever we
build a DLL. We can check the details of the manifest of the assembly by using classes located in
the System.Reflection namespace.

Thus, we can create two types of ASP.NET Assemblies in ASP.NET: private ASP.NET
Assemblies and shared assemblies. Private ASP.NET Assemblies are created when you build
component files like DLLs that can be applied to one application.

Shared ASP.NET Assemblies are created when you want to share the component files across
multiple applications. Shared ASP.NET Assemblies must have a unique name and must be
placed in Global Assembly Cache (GAC). The GAC is located in the Assembly directory in
WinNT. You can view both the manifest and the IL using ILDisassembler (ildasm.exe).

Q30. List and Explain the Components of

assemblies.
 An assembly is a fundamental building block of any .NET framework application. It contains the
code that is executed by common language runtime. For example, when we build a simple C#
application, Visual Studio creates an assembly in the form of a single portable executable (PE)
file, specifically an EXE or DLL.

31 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Every assembly has a file called ‘​manifest’ ​file that stores all information about that assembly.
This information’s are known as metadata.

The manifest file contains all the metadata needed to specify the assembly's version
requirements, security identity, and all metadata needed to define the scope of the assembly
and resolve references to resources and classes.

Components of
Assembly

Manifest ​It describes the assembly. The manifest file contains all the metadata needed to
specify the assembly's version requirements, security identity, and all metadata needed to
define the scope of the assembly and resolve references to resources and classes.

Type Metadata ​It contains metadata, which describes each type (class, structure,
enumeration, and so forth​)

MSIL ​It contains Intermediate language

code.

Resources ​It contains bitmaps, icons, audios and other

types of resources​.

Q31. Difference between public assembly and private

assembly
Q32. How Garbage collector
works.

Every time our application instantiates a reference-type object, the CLR allocates space on the
managed heap for that object.

However, we never need to clear this memory manually. As soon as our reference to an object
goes out of scope (or our application ends), the object becomes available for garbage collection.
The garbage collector runs periodically inside the CLR, automatically reclaiming unused memory
for inaccessible objects.

The .NET Framework provides automatic memory management called garbage collection. A
.NET program that runs in a managed environment is provided with this facility by .NET CLR
(common language runtime).

32 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

The purpose of using Garbage Collector is to clean up memory. In .NET all dynamically
requested memory is allocated in the heap which is maintained by CLR. The garbage collector
continuously looks for heap objects that have references in order to identify which ones are
accessible from the code. Any objects without reference will be removed at the time of garbage
collection. The Garbage collection is not deterministic.

It is called only when the CLR decides that it is most needed. It happens in a situation such as
 the heap for the given process is becoming full and requires a clean-up.

In the common language runtime (CLR), the garbage collector serves as an automatic
memory manager. It provides the following benefits:

▪ Enables you to develop your application without having to free

memory.
▪ Allocates objects on the managed heap efficiently.
▪ Reclaims objects that are no longer being used, clears their memory, and keeps the memory
available for future allocations. Managed objects automatically get clean content to start with, so
their constructors do not have to initialize every data field.
▪ Provides memory safety by making sure that an object cannot use the content of another
object.

GC.Collect ()
method:
▪ This method is used to call garbage collector explicitly. It is used to force a garbage collection to
occur at any time.

Q33. What is namespace? Explain System

namespace.

Namespaces are C# program elements designed to help you organize our programs. They also
provide assistance in avoiding name clashes between two sets of code. Implementing
Namespaces in our own code is a good habit because it is likely to save us from problems later
when we want to reuse some of our code.

For example​, if we created a class named Console, we would need to put it in our own
namespace to ensure that there wasn't any confusion about when the ​System.Console ​class
should be used or when our class should be used. Generally, it would be a bad idea to create a
class named Console, but in many cases your classes will be named the same as classes in
either the .NET Framework Class Library or namespaces help us to avoid the problems that
identical class names would cause.

System is fundamental namespace for C# application. It contains all the fundamental classes
and base classes which are required in simple C# application. These classes and sub classes
defines reference data type, method and interfaces. Some classes provide some other feature
like data type conversion, mathematical function.

Some functionality provided by System

namespace
 ▪ Commonly-used value
▪ Mathematics
▪ Remote and local program invocation
▪ Application environment management
▪ Reference data types
▪ Events and event handlers
▪ Interfaces Attributes Processing exceptions
▪ Data type conversion
▪ Method parameter manipulation

Alias of namespace

Below example demonstrate use of alias where A is alias for

System.Consolenamespaces.

33 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

using A=System.Console;

class Abc { ​public static void

Main() {​ ​A.Write(“Welcome to

C# !!!!”); }​ ​}

Q34. List and explain the use of any five namespaces

in c#.

▪ The ​System ​namespace contains fundamental classes and base classes that define
commonly-used value and reference data types, events and event handlers, interfaces, attributes,
and processing exceptions.

▪ The ​System.Collections ​namespace contains interfaces and classes that define various
collections of objects, such as lists, queues, bit arrays, hash tables and dictionaries.

▪ The ​System.Text.RegularExpressions ​namespace contains classes like Regex, Match and

MatchCollection Class that provide access to the .NET Framework regular expression engine.

▪ The ​System.Data ​namespace provides access to classes that represent the ADO.NET
architecture. ADO.NET lets you build components that efficiently manage data from multiple data
sources.

▪ The ​System.Drawing ​parent namespace contains types that support basic GDI+ graphics
functionality.

Q35. What are the different types of collections in .NET?

Explain.

Collection​: Collections are basically group of records which can be treated as a one
logical unit. .NET Collections are divided in to four important categories as follows.

▪ Indexed based.
▪ Key Value Pair.
▪ Prioritized Collection.
▪ Specialized Collection.

Indexed based: ​It helps us to access the value by using generated index
number by the collection.

ArrayList​: A simple resizable, index-based collection of

objects.

Key Value Pair: ​It helps you to access value by the user defined
key.

SortedList​: A sorted collection of name/value pairs of objects. ​Hashtable​: A collection

of name/value pairs of objects that allows retrieval by name or index

Prioritized Collection​: ​It helps us to get the element in a particular

sequence.

Queue​: A first-in, first-out collection of objects

Stack​: A last-in, first-out collection of objects

Specialized Collection​: ​It is very specific collections which are meant for very specific purpose
like hybrid dictionary that start as list and become Hashtable.

StringCollection​: A simple resizable collection of strings ​StringDictionary: ​A collection of

name/values pairs of strings that allows retrieval by name or index ​ListDictionary​: An efficient
collection to store small lists of objects

34 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

 HybridDictionary​: A collection that uses a ListDictionary for storage when the number of items
in the collection is small, and then migrate the items to a Hashtable for large collections

Q36. What is ArrayList? Explain Property and Methods of

ArrayList.

ArrayList is a non-generic type of collection in C#. It can contain elements of any data types. It is
similar to an array, except that it grows automatically as you add items in it. Unlike an array, we
don't need to specify the size of ArrayList.

Example​: Initialize ArrayList ​ArrayList

myArryList = new ArrayList();

Properties and Methods of

ArrayList

Example: Add elements into

ArrayList

ArrayList arryList1 = new

ArrayList(); arryList1.Add(1);
arryList1.Add("Two");
 arryList1.Add(3); arryList1.Add(4.5);

ArrayList arryList2 = new

ArrayList(); arryList2.Add(100);
arryList2.Add(200);

//adding entire arryList2 into arryList1

arryList1.AddRange(arryList2);

Example: Insert() ​ArrayList myArryList

= new ArrayList(); myArryList.Add(1);
myArryList.Add("Two");
myArryList.Add(3);

35 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

myArryList.Add(4.5);

myArryList.Insert(1, "Second Item");

myArryList.Insert(2, 100);

Example: Remove() ​ArrayList arryList1 = new

ArrayList(); arryList1.Add(100);
arryList1.Add(200); arryList1.Add(300);
arryList1.Remove(100); //Removes 1 from
ArrayList

Example: RemoveAt() ​ArrayList arryList1 = new ArrayList();

arryList1.Add(100); arryList1.Add(200); arryList1.Add(300);
arryList1.RemoveAt(1); //Removes the first element from an
ArrayList

Example: Contains() ​ArrayList

myArryList = new ArrayList();
myArryList.Add(100);
myArryList.Add("Hello World");
myArryList.Add(300);

Console.WriteLine(myArryList.Contains(100)
);

Q37. What is generic class? Explain with

 example.
Generics introduced in C# 2.0. Generics allow us to define a class with placeholders for the type
of its fields, methods, parameters, etc. Generics replace these placeholders with some specific
type at compile time. A generic class can be defined using angle brackets <>. For example, the
following is a simple generic class with a generic member variable, generic method and
property. ​Example: ​class MyGenericClass<T> {
private T genericMemberVariable;

public MyGenericClass(T
value) {
genericMemberVariable =
value; }

public T genericMethod(T
genericParameter) {
Console.WriteLine("Parameter type: {0}, value: {1}",
typeof(T).ToString(),genericParameter); Console.WriteLine("Return type: {0}, value: {1}",
typeof(T).ToString(), genericMemberVariable);

return genericMemberVariable;
}

public T genericProperty { get;

set; } }

36 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

MyGenericClass<int> intGenericClass = new
MyGenericClass<int>(10);

int val =
intGenericClass.genericMethod(200);

As we can see in the above code, MyGenericClass is defined with <T>. <> indicates that
MyGenericClass is generic and the underlying type would be defined later, for now consider it as
T. We can take any character or word instead of T. ​Output: ​Parameter type: int, value: 200
Return type: int, value: 10

Q38. How to create and user property in

 C#.
In C#, properties are nothing but natural extension of data fields. They are usually known as
'​smart fields​' in C# community. We know that data encapsulation and hiding are the two
fundamental characteristics of any object-oriented programming language.

In C#, data encapsulation is possible through either classes or structures. By using various
access modifiers like private, public, protected, internal etc it is possible to control the
accessibility of the class members. Usually inside a class, we declare a data field as private and
will provide a set of public SET and GET methods to access the data fields. In C#, properties are
defined using the property declaration syntax. The general form of declaring a property is as

follows. <acces_modifier> <return_type> <property_name> { ​get {​ ​} set {​ ​} } ​Example​:

using ​System; ​class ​MyClass { ​private

int ​x; public

​ int ​X { ​get {​ ​return ​x; }​ ​set {​

x = ​value​; }​ ​} } ​class ​MyClient {​ ​public

static void ​Main() {​ ​MyClass mc = ​new

MyClass();

37 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

mc.X = 10; ​int ​xVal = mc.X;
Console.WriteLine(xVal);​//Displays 10 ​} ​}

Q39. What is delegate? Explain the steps to implement delegate in

C#.NET.

Delegate:

The dictionary meaning of ‘Delegates’ is “A person acting for another person”. A delegate in C#
is a class type object & is used to invoke a method that has been encapsulated into it at the time
of its creation.

Following steps are used to create delegate: Delegate

declaration ​modifier delegate return_type
delegate_name(parameters) ​Delegate methods definition

modifier function_name(parameters) { ​//statement(s) }​

Delegate instantiation new

​ delegate_type(expression);
Delegate invocation ​Delegate_object (parameters); ​Note:
 signature of delegate and function must be same ​Example:
public delegate void MyDelegate(int , int );

class Abc { ​public void Addition(int a, int b) {​

Console.WriteLine (“Addition :”+(a+b)); }​ ​public

void Subtraction(int a, int b) {​ ​Console.WriteLine

(“Subtraction :”+(a-b)); }​ ​} class Xyz {​ ​public static

void Main() {​ ​Abc a1=new Abc(); MyDelegate

​
m1=new MyDelegate(a1.Addition); MyDelegate
m2=new MyDelegate(a1.Subtraction); m1(10,20);
m2(40,5); Console.Read();

38 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

} ​}

Q40. What is delegate? Explain multiple delegate with

example.

Delegate: ​A delegate in C# is similar to a function pointer in C or C++. It is a reference type

object that allows the programmer to encapsulate a reference to a method in it. It defines the
return type and signature for a method and can refer to any methods that are of the same format
in the signature.

When same delegate is used to call method multiple time then it is referred as Multicast
delegate or Multiple delegate.

Following are condition for multicast delegate:

▪ void is used as return type

▪ Out parameter is not allowed as arguments

Example

public delegate void MyDelegate();

class Abc { ​public void Show() {​

Console.WriteLine (“New Delhi”); }​ ​public void

 Display() {​ ​Console.WriteLine (“New York”); }​

} class Xyz {​ ​public static void Main() {​ ​Abc

a1=new Abc(); MyDelegate

​ m1=new
MyDelegate(a1.Show); MyDelegate m2=new
MyDelegate(a1.Display);
m1=m1+m2+m1+m2-m1; m1();
Console.Read();

} ​Q41. Delegates in C# are used for Event Handling. Justify this statement with a

relevant example program.

​
Events: ​An important C# feature is built upon the foundation of delegates: the event. An event
is, essentially, an automatic notification that some action has occurred. Events work like this: An
object that has an interest in an event registers an event handler for that event. When the event
occurs, all registered handlers are called. Event handlers are represented by delegates. Events
are members of a class and are declared using the event keyword.

39 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Its most commonly used form is shown
here:

event event-delegate
event-name;

Here, ​event-delegate ​is the name of the delegate used to support the event, and event-name is
the name of the specific event object being declared.

Example:

using System;

delegate void MyEventHandler();

class MyEvent { ​public event

MyEventHandler SomeEvent; public

​ void
OnSomeEvent() { if(SomeEvent != null)

SomeEvent(); } ​} class EventDemo {​

 static void Handler() {
Console.WriteLine("Event occurred"); }

static void Main() {​ ​MyEvent evt = new

MyEvent(); evt.SomeEvent
​ += Handler;

evt.OnSomeEvent(); } ​}

40 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

 Unit-II
Topics: Web Form Fundamentals
|Form Controls
41 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
Q1. List and explain different files and folder in ASP.NET web
application.

ASP.NET File Types: - ​ASP.NET applications can include many types of files. Below table
show list of files.

File Name Description ​.aspx These are ASP.NET web pages. They contain the user interface
and, optionally, the underlying application code. Users request or navigate directly to one of
these pages to start our web application .ascx These are ASP.NET user controls. User controls
are similar to web pages, except that the user can’t access these files directly. Instead, they
must be hosted inside an ASP.NET web page. User controls allow you to develop a small piece
of user interface and reuse it in as many web forms as you want without repetitive code.
web.config This is the configuration file for your ASP.NET application. It includes settings for
customizing security, state management, memory management, and much more. global.asax
This is the global application file. You can use this file to define global variables (variables that
can be accessed from any web page in the web application) and react to global events (such as
when a web application first starts). .cs These are code-behind files that contain C# code. They
allow you to
 separate the application logic from the user interface of a web page.

ASP.NET Web Folders. ​Every web application starts with a single location, called the root
folder. However, in a large, well-planned web application.

Directory Description ​App_Code Contains source code files that are dynamically compiled for
use in
our application App_GlobalResources Stores global resources that are accessible to every page
in the web application. This directory is used in localization scenarios, when we need to have a
website in m​ ore than one language. ​App_Data Stores data, including SQL Server Express database
files App_Themes Stores the themes that are used to standardize and reuse
formatting in our web ​application.

Q2. Explain the three layer architecture of

ASP.NET.

Asp.net architecture consists of 3 layers as

follows:

Presentation Layer ​The presentation layer consists of the Asp.net page that manages the
appearance of application. This layer can include bound data controls and ObjectDataSource
objects that bind data controls to the data.

Middle Layer ​The middle layer contains the data access classes that manage the data access
for the application. This layer can also contain business objects that represent business entities
such as customers, products or employee and that implement business rules such as credit and
discount policies.

Database Layer
This layer consists of the database that contains the data for the application. Ideally the SQL
statement that do the database access should be saved in stored procedure within the
database, nut the SQL statement are often stored in the data access classes.

42 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Q3. Explain ASP.NET Life Cycle
Page.
ASP.NET life cycle specifies,
how:
• ​ASP.NET processes pages to produce dynamic
output
• ​The
application and its pages are instantiated and
processed
• ​ASP.NETcompiles the pages dynamically When a page is requested, it is loaded into
the server memory, processed and sent to the browser. Then it is unloaded from the memory. At
each of this steps, methods and events are available, which could be overridden according to
the need of the application.
 Following are the different stages of an ASP.Net
page:

Page request ​When ASP.Net gets a page request, it decides whether to parse and compile the page
or there would be a cached version of the page; accordingly the response is sent

Starting of page life cycle: ​At this stage, the Request and Response objects are set. If the
request is an old request or post back, the IsPostBack property of the page is set to true.

Page initialization ​At this stage, the controls on the page are assigned unique ID by setting the
UniqueID property and themes are applied.

43 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Page load ​At this stage, control properties are set using the view state and
control state values.

Validation ​Validate method of the validation control is called and if it runs successfully, the
IsValid property of the page is set to true.

Postback event handling ​If the request is a postback (old request), the
related event handler is called.

Page rendering ​At this stage, view state for the page and all
controls are saved.

Unload ​The rendered page is sent to the client and page properties, such as Response and
Request are unloaded and all cleanup done.

Following are the page life cycle

 events:

PreInit() Init()
InitComplete()
LoadViewState()
LoadPostData()
PreLoad() Load​()
LoadComplete()
PreRender()
PreRenderComplete​()
SaveStateComplete()
UnLoad()

Q4. Differentiate between inline code and code

behind

44 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Q.5Difference between HTML control and Web Server control.
HTML control Web Server control ​HTML control runs at ​client side. ​ASP.Net controls
run at ​server side​. We can run HTML controls at server side by adding attribute
runat=”server”​.
Wecannot run ASP.Net Controls on client side as these controls have this attribute
 runat=”server” ​by default​. ​HTML controls are client side controls, so it does not provide
STATE management.
ASP.Net Controls are Server side controls, provides STATE management. HTML control
does not require rendering. HTML control does not require rendering. As HTML controls
runs on client side, execution is ​fast​.
As ASP.Net controls run on server side, execution is ​slow​. HTML controls does not support
Object Oriented paradigm​.
With ASP.Net controls, you have full support of Object oriented paradigm. HTML control
have ​limited ​set of properties and/or methods.
ASP.Net controls have ​rich ​set of properties and/or methods. <input type="text"
ID="txtName"> <asp:TextBoxId="txtName"runat="server">
</asp:TextBox>
Q.6 Short note on Page class.
When an ASP.NET page is requested and renders markup to a browser, ASP.NET creates
an instance of a class that represents our page. That class is composed not only of the
code that we wrote for the page, but also code that is generated by ASP.NET. ​Page
Properties
Property Description ​IsPostBack This Boolean property indicates whether this is the first
time the page is being run (false) or whether the page is being resubmitted in response to a
controlevent, typically with stored view state information (true). EnableViewState When set
to false, this overrides the EnableViewState property of the contained controls, thereby
ensuring that no controls will maintain state information. Application This collection holds
information that’s shared between all users in our website. For example, we can use the
Application collection to count the number of times a page has been visited. Session This
collection holds information for a single user, so it can be used in different pages. For
example, we can use the Session collection to store the items in the current user’s
shopping basket on an e-commerce website. Request This refers to an HttpRequest object
that contains information about the current web request. We can use the HttpRequest
object to get information about the user’s browser. Response This refers to an
HttpResponse object that represents the response
ASP.NET will send to the user’s browser
Q7. Explain the use of global.asx and web.config files in ASP.NET application.
OR Explain the files used to configure an ASP.NET Application.
▪ The Global.asax file, also known as the ASP.NET application file, is an optional file
that contains code for responding to application-level events raised by ASP.NET or by
HttpModules.
▪ The Global.asax file resides in the root directory of an ASP.NET-based application.
The Global.asax file is parsed and dynamically compiled by ASP.NET.
45 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
▪ The Global.asax file itself is configured so that any direct URL request for it is automatically
rejected; external users cannot download or view the code written within it.

▪ The Global.asax file does not need recompilation if no changes have been made to it. There can
be only one Global.asax file per application and it should be located in the application's root
directory only.

The Global.asax contains two types of events those

are
o Events which are fired for every request o
Events which are not fired for every request

Events which are fired for every request:-

Application_BeginRequest() ​– This event raised at the start of every request for the web application.
Application_EndRequest() ​– This event raised at the end of each request right before the objects
released. ​Application_PreRequestHandlerExecute() ​– T​his event called before the appropriate
HTTP handler executes the request. ​Application_PostRequestHandlerExecute() ​– T ​ his event
called just after the request is handled by its appropriate HTTP handler.

Events which are not fired for every request:-

Application_Start() ​– ​This event raised when the application starts up and application domain is
created. ​Session_Start() ​– ​This event raised for each time a new session begins, This is a good
place to put code that is session-specific. ​Application_Error() ​– ​This event raised whenever an
unhandled exception occurs in the application. This provides an opportunity to implement
generic application-wide error handling. ​Session_End() ​– ​This event called when session of user
​ pplication_End() ​– ​This event raised just before when web application ends.
ends. A
Application_Disposed() ​– ​This event fired after the web application is destroyed and this event is
used to reclaim the memory it occupies.

Web.Config

▪ ​Configuration file is used to manage various settings that define a website. The settings are
stored in XML files that are separate from our application code. In this way we can configure
settings independently from our code.
▪ ​Generally a website contains a single Web.config file stored inside the application root directory.
However there can be many configuration files that manage settings at various levels within an
application.
▪ There are number of important settings that can be stored in the configuration file. Some of the
most frequently used configurations, stored conveniently inside Web.config file are:
- Database connections -
Caching settings - Session
 States - Error Handling -
Security

Benefits of XML-based Configuration

files
▪ ASP.NET Configuration system is extensible and application specific information can be stored
and retrieved easily. It is human readable.
▪ We need not restart the web server when the settings are changed in configuration file. ASP.NET
automatically detects the changes and applies them to the running ASP.NET application.
Configuration file looks like this

46 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

1. ​<configuration> ​2. ​<connectionStrings> ​3. ​<add name=​"myCon"
connectionString=​"server=MyServer;database=puran;uid=p
uranmehra;pwd=mydata1223" ​/>
4. ​</connectionStrings> ​5. ​</configuration/>

Q8. Explain TextBox control in ASP.NET with any five

properties.

This is an input control which is used to take user input. To create ​TextBox ​either we can write code
or use the drag and drop facility of visual studio IDE. This is server side control, asp provides own
tag to create it. The example is given below. ​< asp:TextBoxID="TextBox1" runat="server"
></asp:TextBox>

This control has its own properties that are tabled below.

Property Description ​Text It is used to set text to be shown for the

control.

MaxLength It is used to set maximum number of characters that can be entered.

Readonly It is used to make control readonly.

TextMode It used to determine behavior of control. Possible value are Single / Multiline
/ Password

CausesValidation true/false – It is used to enable or disable validation effect on control

Example: ​Assign a text to TextBox control when Button click event fires
using c#
 C# code for above TextBox ExampleC# ​protected void

btndisplay_Click(object sender, EventArgs e) { ​TextBox1.Text

= "Asp.net"; }​ ​protected void btnclear_Click(object sender,

EventArgs e) {​ ​TextBox1.Text = ""; }​

Q9. What is the difference between buttons, Link Buttons and Image Buttons? Explain any
three
common button attributes.

These controls differ only in how they appear to the user. A button displays text within a rectangular
area. A Link button displays text that look like a hyperlink and an image button displays an image.
LinkButton ​control is a control just like a Button control along with the flexibility to make it look like a Hyperlink. It
implements an anchor <a/> tag that uses only ASP.NET postback mechanism to post the data on the server. Despite
being a hyperlink, we can't specify the target URL. ​ImageButton ​control is used to post the form or fire an event
either client side or server side. It’s like a asp:Button control, the only difference is, we have the ability to place our
own image as a

47 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

button. ImageButton control is generally used to post the form or fire an event either client side or server side.

Button ​control is used to post the form or fire an event either client side or server side. Button control is generally
used to post the form or fire an event either client side or server side. When it is rendered on the page, it is generally
implemented through <input type=submit> HTML tag.
Q10. Explain CheckBox and RadioButton web server controls in
ASP.NET.
CheckBox: ​CheckBox control is an asp.net web server control. CheckBox control visually as square
on web forms. The Checkbox control allow user to check square or uncheck square. In CheckBox
control check and uncheck checkbox specify by the checked property of check box true or false.
Basic syntax for check box: <asp:CheckBox ID= "chkoption" runat=
"Server"></asp:CheckBox>

CheckBox properties:

▪ ​AutoPostBack:​Specifies whether the form should be posted immediately after the Checked property
has changed or not. Default is false
▪ ​CausesValidation:​Specifies if a page is validated when a Button control is clicked
▪ ​Checked:​Specifies whether the check box is checked or not
▪ ​Id:​A unique id for the control
▪ ​Text: The ​text next to the check box

Event: OnCheckedChanged ​The name of the function to be executed when the

checked property has changed

RadioButton ​Radiobutton isasp.net web server control. Radiobutton is used to allow user to select a
 single radiobutton from group of radiobutton. In asp.net generally we use more than one radiobutton
and select only one radiobutton at a time from all the radiobutton control. On other hand in ​checkbox
control ​we can check and uncheck multiple check box at a time.

48 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Basic syntax for radio button: <asp:RadioButton ID= "rdboption" runat=
"Server"></asp: RadioButton>

RadioButton properties:

▪ ​AutoPostBack:​A Boolean value that specifies whether the form should be posted immediately after
the Checked property has changed or not. Default is false
▪ ​Checked ​: A Boolean value that specifies whether the radio button is checked or not ​id ​a unique id
for the control
▪ ​GroupName ​: The name of the group to which this radio button belongs
▪ ​Text ​: The text next to the radio button

Q11. Explain Listbox with properties and

methods.

ListBox control is an asp.net web server control. ListBox control used to store the multiple items and
allow user to select multiple item from ListBox control. ListBox control is same as dropdownlist
control. The dropdownlist control allow user to select maximum only one item at a time, on other
hand ListBox control allow user to select multiple items same time. So we can also say ListBox is
multi- row selection box control. In a ListBox control there is a SelectionMode property to change the
mode of section from single to multiple. By default ListBox control selection mode is single if we want
to select multiple items from ListBox, then just change the SelectionMode property to multiple.

<asp:ListBox ID="dropStatic" runat="server">

<asp:ListItem Text="Red" Value="red"></asp:ListItem>
<asp:ListItem Text="Blue"
Value="blue"></asp:ListItem> <asp:ListItem
Text="Green" Value="green"></asp:ListItem>
</asp:ListBox>

Some properties are

 Following are the important methods and
events:

GetSelectedIndices

▪ Gets the array of index values for currently selected items in the ListBox
control.
▪ public virtual int[] GetSelectedIndices()
▪ Say for example, if ID of the list box is ‘ListBox1’ then the following code displays all selected
items from the list box to a label with ID ‘Label1’.

int[] x = ListBox1.GetSelectedIndices(); Label1.Text

= ""; for (int i = 0; i < x.Length; i++) Label1.Text +=
ListBox1.Items[x[i]].Text + "<br>";
SelectedIndexChanged

49 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

SelectedIndexChanged event occurs when the selection from the list control changes between
posts to the server.

OnSelectedIndexChange
d

▪ OnSelectedIndexChanged method raises the SelectedIndexChanged

event.
▪ This allows you to provide a custom handler for the
event.

Q12. What is the difference between List Box and Drop-Down Lists? List and explain any
three common
properties of these
controls.

▪ List boxes are used in cases where there are small numbers of items to be selected. In contrast,
drop-down lists are typically used with larger list so that they don’t take up much space on the
page.

▪ A list box lets a user select one or more items from the list of items. A drop-down list lets a user
choose an item from the drop-down list of items.

Following are common properties of ListBox and

DropDownList:

Properties Description ​Items Gets the collection of items from the dropdown
box. SelectedValue Get the value of the Selected item from the dropdown box.
SelectedIndex Gets or Sets the index of the selected item in the dropdown box.
SelectedItem Gets the selected item from the list.

Q13. Explain any five Methods/Property of List Item collection

objects.

Following is list of Methods/Property of List Item collection

objects:

Q14. Explain Sorted, SelectedMode, MultiColumn, SelectedItem and SelectedIndex

properties of ListBox control.

Sorted ​The Sorted property set to true, the ListBox items are sorted. The following code snippet
sorts the ListBox items.
 listBox1.Sorted = true;

50 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Selected Mode:

SelectionMode property defines how items are selected in a ListBox. The SelectionMode value
can be one of the following four SelectionMode enumeration values. ​None ​- No item can be
selected. ​One ​- Only one item can be selected. ​MultiSimple ​- Multiple items can be selected.
MultiExtended ​- Multiple items can be selected, and the user can use the SHIFT, CTRL, and
arrow keys to make selections.

listBox1.SelectionMode =
SelectionMode.MultiSimple;

listBox1.SetSelected(1, true);
listBox1.SetSelected(2, true);

MultiColumn: ​A multicolumn ListBox places items into as many columns as are needed to
make vertical scrolling unnecessary. The user can use the keyboard to navigate to columns that
are not currently visible. Set the HorizontalScrollbar property to true to display a horizontal scroll
bar that enables the user to scroll to columns that are not currently shown in the visible region of
the ListBox. The value of the ColumnWidth property determines the width of each column.

listBox1.MultiColumn = true;

SelectedItem ​Gets or sets the currently selected item in the ListBox. We can get text associated
with currently selected item by using Items property.

string selectedItem =
listBox1.Items[listBox1.SelectedIndex].ToString();

SelectedIndex ​Gets or sets the zero-based index of the currently

selected item in a ListBox.

listBox1.SelectedIndex = 1;

Q15. Explain Table control with example in

ASP.NET

Table control is used to structure a web pages. In other words to divide a page into several rows
and columns to arrange the information or images. When it is rendered on the page, it is
implemented through <table> HTML tag.

We can simply use HTML <table> control instead of using ​<asp:Table> ​control. However many of
 one benefits of using <​asp:Table> ​control is we can dynamically add rows or columns at the
runtime or change the appearance of the table. Following are some important ​properties ​that are
very useful. ​BackImageUrl ​Used to set background image of the table ​Caption ​Used to write the
caption of the table.

Example:
ASP.NET code for a table control
<​asp​:​Table ​ID​="Table1" ​runat​="server" ​Height​="123px" ​Width​="567px">
<​asp​:​TableRow ​runat​="server">
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​>
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​>
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​>
</​asp​:​TableRow​> <​asp​:​TableRow ​runat​="server">
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​>
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​>
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​>
</​asp​:​TableRow​>

51 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

<​asp​:​TableRow ​runat​="server">
<​asp​:​TableCell ​runat​="server"></​asp​:​TableCell​> <​asp​:​TableCell
runat​="server"></​asp​:​TableCell​> <​asp​:​TableCell
runat​="server"></​asp​:​TableCell​> </​asp​:​TableRow​> </​asp​:​Table​>

Q16. Explain Multiview and View control with example in

ASP.NET
MultiView Control is an asp.net web server control. Multiview Control is a same as Tab control. If
we want make a complex designing on one web forms then you have to use multiview control.

MltiView control is a container of several view control. In a multiview control there are many view
control for designing separation of view for user.

The View control is a container of several web server controls. Using the multiview control we
can feel the multiple page view design on a single web page.

We can also say multiview control allow user to create different view on single web page. There
are many view control in a multiview control, each view control has some web server control for
design web page. We can see single view at a time on web page by specify the
ActiveViewIndex ​property of multiview control.

All view control assign automatically index to all it, the index always start from zero. The first
view1 index is zero, second is one and so on, If we want to display first view on web page,
then we need to write ​MultiView1.ActiveViewIndex=0​.
 • ​Prefix for MultiView control is mv
• ​Prefix
for View control is v The MultiView control
has the following important properties:

Q17. Explain Adrotator control with example in

ASP.NET
The AdRotator is one of the rich web server control of asp.net. AdRotator control is used to
display a sequence of advertisement images as per given priority of image.

Adrotator control display the sequence of images, which is specified in the external XML file. In
xml file we indicate the images to display with some other attributes, like image impressions,
NavigateUrl, ImageUrl, AlternateText.

52 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

In Adrotator control images will be changed each time while refreshing the web
page.

AdRotator Control Example in

ASP.Net
The basic syntax of adding an AdRotator is as
follows:
<asp:AdRotator runat = "server" AdvertisementFile = "adfile.xml" /> ​The advertisement file
is an XML file, which contains the information about the advertisements to be displayed. There
are the following standard XML elements that are commonly used in the advertisement file:

The following code illustrates an advertisement file ads.xml:

<Advertisements> <Ad> <ImageUrl>rose1.jpg</ImageUrl>
<NavigateUrl>http://www.1800flowers.com</NavigateUrl>
<AlternateText>
Order flowers, roses, gifts and more </AlternateText>
<Impressions>20</Impressions>
<Keyword>flowers</Keyword> </Ad> <Ad>
<ImageUrl>rose2.jpg</ImageUrl>
<NavigateUrl>http://www.babybouquets.com.au</NavigateUrl
> <AlternateText>Order roses and flowers</AlternateText>
<Impressions>20</Impressions> <Keyword>gifts</Keyword>
</Ad> <Ad> <ImageUrl>rose3.jpg</ImageUrl>
<NavigateUrl>http://www.flowers2moscow.com</NavigateUrl
> <AlternateText>Send flowers to Russia</AlternateText>
<Impressions>20</Impressions>
<Keyword>russia</Keyword> </Ad> </Advertisements>
53 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
Create a new web page and place an AdRotator control on it. ​<form
id="form1" runat="server"> <div> <asp:AdRotator ID="AdRotator1"
runat="server" AdvertisementFile ="~/ads.xml"
onadcreated="AdRotator1_AdCreated" /> </div> </form>

Q18. Explain Calendar control with example in

ASP.NET

ASP.NET provides a Calendar control that is used to display a calendar on the Web page. This
control displays a one-month calendar that allows the user to select dates and move to the next
and previous months.

By default, this control displays the name of the current month, day headings for the days of the
weeks, days of the month and arrow characters for navigation to the previous or next month.
The class hierarchy for this control is as follows

Object->Control->WebControl->Calendar

The Calendar is complex, powerful Web server control that you can use to add calendar
feature to our web page. We can use calendar control display any date between 0 A.D. and
9999A.D.The Calendar control is represented as:

<​asp​:​Calendar ​ID​="Calendar1" ​runat​="server"></​asp​:​Calendar​>

The Calendar control when rendered to a user browser, it generates an HTML <table> element
and a set of associated JavaScript. The Calendar control can be used to select a single date or
multiple dates. The ​SelectionMode ​property is used for this. The ​SelectionMode ​properties are
 as:

54 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Q19. Explain any five common properties of web server
controls.

Following are common properties of web server controls:

Q20. What is use of autopostback and runat

properties?

▪ AutoPostback or Postback is nothing but submitting page to server. AutoPostback is webpage

 going to server, Server processes the values and sends back to same page or redirects to
different page.
▪ HTML elements in ASP.NET files are, by default, treated as text. To make these elements
programmable, add a runat="server" attribute to the HTML element. This attribute indicates that
the element should be treated as a server control.
▪ The runat="server" attribute indicates that the form should be processed on the server. It also
indicates that the enclosed controls can be accessed by server scripts.
▪ AutoPostBack means that if any change happens on a control by the client, it should postback to
the server to handle that change at server side. If this property is set to TRUE the automatic post
back is enabled, otherwise FALSE. Default is FALSE.

Example

<asp:TextBox id= " t1" AutoPostBack="true" runat="server"

/>

Web server controls are created on the server and they require a runat="server" attribute to
work. This attribute indicates that the control should be treated as a server control.

Q21. Explain UrlEncode() and UrlDecode() methods in

ASP.NET.

We cannot send special characters through query string. All special characters should be
encoded when you pass them through the query string. The encoded string must be decoded at
the receiver. There are two methods to achieve this: ​UrlEncode and UrlDecode()​:

The main purpose of these two methods is to encode and decode the ​URL​respectively. We
need to encode the URL because some of the characters are not safe sending those across
browser. Some characters are being misunderstood by the browser and that leads to data
mismatch on the receiving end. Characters such as a question mark (?), ampersand (&), slash
mark (/), and spaces might be truncated or corrupted by some browsers.

55 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

UrlEncode() ​This method is used to encode a string to be passed through URL to another web
page. URLencode replaces unsafe ASCII characters with a "%" followed by two hexadecimal
digits. ​Syntax​: ​UrlEncode (string str )

UrlDecode() ​This method is used to decode the encoded URL string. Decodes any %##
encoding in the given string. ​Syntax: ​UrlDecode (string str )

Q22.What is user control? How to create and use user control in

ASP.NET Page.

A UserControl is a separate, reusable part of a page. We can put a piece of a page in a

UserControl, and then reuse it from a different location. A notable difference is that User
Controls can be included on multiple pages, while a page can't.

UserControls are used much like regular server controls, and they can be added to a page
declaratively, just like server controls can.

A big advantage of the UserControl is that it can be cached, using the OutputCache functionality
described in a previous chapter, so instead of caching an entire page, we may cache only the
UserControl, so that the rest of the page is still re-loaded on each request. ​Creation of
UserControl: ​Following steps are used to create UserControl.

1. Open Visual Studio. 2. "File" -> "New" -> "Project..." then select ASP.NET Webform
Application. 3. Add a new web form. To create a new UserControl, in Solution Expolrer, Add
New Item, provide your File Name and click Add Design UserControl as per our requirement.
Next step to use UserControl in .aspx page. Add the following line below the standard page
declaration:

<%@RegisterTagPrefix="My"TagName="UserInfoBoxControl"Src="~/UserInfoBoxCont rol.ascx"
%>

Make sure that the src value matches the path to your UserControl file. Now you may use the
UserControl in your page, like any other control. For instance, like this:

<My:UserInfoBoxControlrunat="server"ID="MyUserInfoBoxControl"/>

Q23.Why we use validation controls? List various types of controls used

in asp.net

Validation is important part of any web application. User's input must always be validated before
sending across different layers of the application.

Validation controls are used

to:

▪ Implement presentation logic.

▪ To validate user input data.
▪ Data format, data type and data range is used for
validation.
 ▪ Validation Controls in ASP.NET

56 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

An important aspect of creating ASP.NET Web pages for user input is to be able to check that
the information users enter is valid. ASP.NET provides a set of validation controls that provide
an easy-to- use but powerful way to check for errors and, if necessary, display messages to the
user.

There are six types of validation controls in

ASP.NET

▪ RequiredFieldValidation Control
▪ CompareValidator Control
▪ RangeValidator Control
▪ RegularExpressionValidator Control
▪ CustomValidator Control
▪ ValidationSummar

The below table describes the controls and their

work:

Validation Control Description ​RequiredFieldValidation Makes an input control a required

field CompareValidator Compares the value of one input control to the value of another
input control or to a fixed value RangeValidator Checks that the user enters a value that
falls between two values RegularExpressionValidator Ensures that the value of an input
control matches a specified
pattern CustomValidator Allows you to write a method to handle the validation of the value
entered ValidationSummary Displays a report of all validation errors occurred in a Web
page

Q24.Explain following validation

controls.

RequiredFieldValidator
Control

The RequiredFieldValidator control is simple validation control, which checks to see if the data is
 entered for the input control. We can have a RequiredFieldValidator control for each form
element on which you wish to enforce Mandatory Field rule.

The syntax of the control is as

given:

<asp:RequiredFieldValidator ID="rfvcandidate" runat="server"

ControlToValidate="txtName" ErrorMessage="Please enter name
!!"></asp:RequiredFieldValidator>

RangeValidator
Control

The RangeValidator Server Control is another validator control, which checks to see if a control
value is within a valid range. The attributes that are necessary to this control are:
MaximumValue, MinimumValue, and Type.

It has three specific properties:

The syntax of the control is as

given:

<asp:RangeValidator ID="rvclass" runat="server"

ControlToValidate="txtclass"

57 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

ErrorMessage="Enter your class (6 - 12)"
MaximumValue="12" MinimumValue="6" Type="Integer">

</asp:RangeValidator>

RegularExpressionValidat
or

The RegularExpressionValidator allows validating the input text by matching against a

pattern of a regular expression. The regular expression is set in the ValidationExpression
 property.

The syntax of the control is as

given:

<asp:RegularExpressionValidator ID="string" runat="server"

ErrorMessage="string"
ValidationExpression="string"
ValidationGroup="string">

</asp:RegularExpressionValidato
r

Q25. What is the use of Compare Validator? Explain it along with its
properties.

CompareValidator
Control

▪ The CompareValidator control allows you to make comparison to compare data entered in an
input control with a constant value or a value in a different control.
▪ It can most commonly be used when you need to confirm password entered by the user at
the registration time. The data is always case sensitive.
▪ It has the following specific properties:

The basic syntax of the control is as follows:

<asp:CompareValidator ID="CompareValidator1"
runat="server"
ErrorMessage="CompareValidato
r"> </asp:CompareValidator>
Example:

Small number:<br /> <asp:TextBox runat="server" id="txtSmallNumber" /><br /><br /> Big
 number:<br /> <asp:TextBox runat="server" id="txtBigNumber" /><br />
<asp:CompareValidator runat="server" id="cmpNumbers"
controltovalidate="txtSmallNumber" controltocompare="txtBigNumber" operator="LessThan"
type="Integer" errormessage="The first number should be smaller than the second number!"
/><br />

Q26. ​Explain the CustomValidator control with

code

The CustomValidator control allows writing application specific custom validation routines for
both the client side and the server-side validation.

58 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

The client-side validation is accomplished through the ClientValidationFunction property. The
client- side validation routine should be written in a scripting language, such as JavaScript or
VBScript, which the browser can understand.

The server-side validation routine must be called from the control's ServerValidate event
handler. The server-side validation routine should be written in any .Net language, like C# or
VB.Net.

Below table shows the properties of

CustomValidator.

Example:

In this below example we will simply check the length of the string in the
TextBox.
 Custom Text:<br /> <asp:TextBox runat="server" id="txtCustom" /> <asp:CustomValidator
runat="server" id="cusCustom" controltovalidate="txtCustom"
onservervalidate="cusCustom_ServerValidate" errormessage="The text must be exactly 8
characters long!" /> <br /><br />

protected void cusCustom_ServerValidate(object sender,

ServerValidateEventArgs e) { ​if(e.Value.Length == 8)
e.IsValid =
true; else

e.IsValid = false; } ​Q27. Explain Menu

control in ASP.NET

The Menu control is used to create a menu of hierarchical data that can be used to navigate
through the pages. The Menu control conceptually contains two types of items. First is
StaticMenu that is always displayed on the page, second is DynamicMenu that appears when
opens the parent item.

Following steps are used to create Menu Control: ​Toolbox > Navigation
> Menu ​or add the following few lines of code snippet.

<asp:Menu ID="Menu1" runat="server" Orientation="Horizontal"> <Items>

<asp:MenuItem Text="HOME" NavigateUrl="~/Default.aspx"
Selected="true" /> <asp:MenuItem Text="HTML"
NavigateUrl="~/HTML.aspx"> <asp:MenuItem Text="HtmlTagList"
NavigateUrl="~/HtmlTagList.aspx" /> </asp:MenuItem>

59 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

<asp:MenuItem Text="CSS" NavigateUrl="~/CSS.aspx">
<asp:MenuItem Text="CssSelectors"
NavigateUrl="~/CssSelectors.aspx" /> </asp:MenuItem> </Items>
</asp:Menu>

Below are the various Properties of Menu

Control
Q28. When to use TreeView control in
ASP.NET

▪ ASP.NET TreeView Web control is used to display hierarchical data (such as a table of
contents) in a tree structure in a Web page.
▪ The TreeView control is made up of TreeNode objects. The TreeView control can be bound to
data.

It supports the following

features:

▪ Automatic data binding, this allows the nodes of the control to be bound to hierarchical data,
such as an XML document.
▪ Site navigation support through integration with the SiteMapDataSource
control.
▪ Node text that can be displayed as either selectable text or
hyperlinks.
▪ Customizable appearance through themes, user-defined images, and
styles.
▪ Programmatic access to the TreeView object model, which allows you to dynamically create
trees, populates nodes, set properties, and so on.
▪ Node population through client-side callbacks to the server (on supported
 browsers).
▪ ​The ability to display a check box next to each
node​.

<asp:TreeView ExpandDepth="1" runat="server">

<Nodes> <asp:TreeNode Text="Employees">
<asp:TreeNode Text="Bradley" Value="ID-1234"
/> <asp:TreeNode Text="Whitney"
Value="ID-5678" /> <asp:TreeNode
Text="Barbara" Value="ID-9101" />
</asp:TreeNode>

60 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

</Nodes>
</asp:TreeView>

▪ Each node in the Tree is represented by a name/value pair (not necessarily unique), defined by
the Text and Value properties of TreeNode, respectively. The text of a node is rendered, whereas
the value of a node is not rendered and is typically used as additional data for handling postback
events.
▪ This example also uses the ExpandDepth property of TreeView to automatically expand the tree
1 level deep when it is first rendered.
▪ The TreeView control is made up of one or more nodes. Each entry in the tree is called a node
and is represented by a TreeNode

Q29. Explain SiteMapPath control in

ASP.NET

▪ The SiteMapPath control basically is used to access web pages of the website from one
webpage to another. It is a navigation control and displays the map of the site related to its web
pages.

▪ This map includes the pages in the particular website and displays the name of those pages.
We can click on that particular page in the Site Map to navigate to that page. We can say that the
SiteMapPath control displays links for connecting to URLs of other pages.
▪ The SiteMapPath control uses a property called SiteMapProvider for accessing data from
databases and it stores the information in a data source.

The representation of the SiteMapPath control is as

 follows:

Root Node->Child
Node

Following steps are used to create Menu

Control: ​Toolbox > Navigation >SiteMapPath

Following are some important ​properties ​that are very

useful.

ParentLevelsDisplayed ​: It specifies the number of levels of parent nodes and then displays
the control accordingly related to the currently displayed node. ​RenderCurrentNodeAsLink ​: It
specifies whether or not the site navigation node that represents the currently displayed page is
rendered as a hyperlink. ​PathSeperator ​: It specifies the string that displays the SiteMapPath
nodes in the rendered navigation path. Style properties of the SiteMapPath class

CurrentNodeStyle ​: It specifies the style used for the display text for the current
node.

RootNodeStyle ​: It specifies the style for the root node style

text.

NodeStyle ​: It specifies the style used for the display text for all nodes in the site navigation
path.

Sitemap file has been included in our project and we can see it in the Solution Explorer. And
now we have to set the URL and title attributes in the sitemap file. ​<?​xml ​version​=​"​1.0​"
encoding​=​"​utf-8​" ​?> <​siteMap ​xmlns​=​"​http://schemas.microsoft.com/AspNet/SiteMap-File-1.0​" ​>
<​siteMapNode ​url​=​"​Default.aspx​" ​title​=​"​myhomepage​" ​description​=​""​>
<​siteMapNode ​url​=​"​myweb1.aspx​" ​title​="​ ​myfirstpage​" ​description​=​"" ​/> <​siteMapNode
url​=​"​myweb2.aspx​" ​title​=​"​mysecondpage​" ​description​=​"" ​/> </​siteMapNode​> </​siteMap​>

61 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

 Unit-III
Topics:

Error Handling, Logging, and Tracing

|State Management |Styles, Themes,
and Master Pages
62 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
Q1. Explain Error Handling in
ASP.NET
Error handling in ASP.NET has three aspects: ​Tracing ​- Tracing the program execution at page
level or application level. ​Error handling ​- Handling standard errors or custom errors at page level
or application level. ​Debugging ​- Stepping through the program, setting break points to analyze
the code. ​Tracing ​To enable page level tracing, you need to modify the Page directive and add a
Trace attribute as shown: ​<%@ Page Language="C#" AutoEventWireup="true"
CodeBehind="Default.aspx.cs" Inherits="errorhandling._Default" Trace ="true" %>

Now when we execute the file, we get the tracing

information:
It provides the following information at the top:
• ​Session ID
• ​Status Code
• ​Time of Request
• ​Type of Request
• ​Request and Response Encoding

The status code sent from the server, each time the page is requested shows the name and
time of error if any. The following table shows the common HTTP status codes: The class of a
status code can be quickly identified by its first digit:

1xx: Informational
2xx: Success 3xx:
Redirection 4xx:
Client Error 5xx:
Server Error

Under the top level information, there is Trace log, which provides details of page life
cycle. It provides elapsed time in seconds since the page was initialized.
63 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
To check the Warn method, let us forcibly enter some erroneous code in the selected index
changed event handler: ​try { ​int a = 0; int
​ b = 9 / a; } ​catch (Exception e) {​ ​Trace.Warn("UserAction",

"processing 9/a", e); }​ ​Try-Catch is a C# programming construct. The try block holds any code that may

or may not produce error and

​ the catch block catches the error. When the program is run, it sends
the warning in the trace log.

Application level tracing applies to all the pages in the web site. It is implemented by putting the
following code lines in the web.config file: <system.web> <trace enabled="true" /> </system.web>

Error Handling ​Although ASP.NET can detect all runtime errors, still some subtle errors may
still be there. Observing the errors by tracing is meant for the developers, not for the users. Hence, to
intercept such occurrence, we can add error handing settings in the web.config file of the application.
It is application-wide error handling. For example, we can add the following lines in the web.config
file: ​<configuration> <system.web>

<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm"> <error

statusCode="403" redirect="NoAccess.htm" /> <error statusCode="404"
redirect="FileNotFound.htm" /> </customErrors>

</system.web>
<configuration>

Q2. What is Debugging? Explain in

ASP.NET
Debugging allows the developers to see how the code works in a step-by-step manner, how the
values of the variables change, how the objects are created and destroyed, etc. When the site is
executed for the first time, Visual Studio displays a prompt asking whether it should be enabled for
 debugging:

When debugging is enabled, the following lines of codes are shown in the
web.config:

64 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

<system.web> <compilation
debug="true"> <assemblies>
.............. </assemblies> </compilation> </system.web>
The Debug toolbar provides all the tools available for
debugging:

Breakpoints ​Breakpoints specifies the runtime to run a specific line of code and then stop execution
so that the code could be examined and perform various debugging jobs such as, changing the
value of the variables, step through the codes, moving in and out of functions and methods etc.

To set a breakpoint, right click on the code and choose insert break point. A red dot appears on the
left margin and the line of code is highlighted as shown:

Next when you execute the code, you can observe its
behavior.
 At this stage, you can step through the code, observe the execution flow and examine the value of
the variables, properties, objects, etc. We can modify the properties of the breakpoint from the
Properties menu obtained by right clicking the breakpoint glyph:

Q3. Why exception handling is required? Write syntax for user define
exception?

Exception handling: ​The mechanism of Exception Handling is throwing an exception and

catching it C# uses try-catch block. Code which may give rise to exceptions is enclosed in a try
block, and Catch block catches that exception and handles it appropriately. The try block is
followed by one or more catch blocks.

Basic syntax:

65 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

try { ​//programming logic(code which may give rise to exceptions) }​ ​catch (Exception e) {​

//message on exception }​ ​finally {​ ​// always executes }​ ​Try:​A try block identifies a block of code

for which particular exceptions will be activated. It's followed

​ by one or more catch blocks.
Catch:​A program catches an exception with an exception handler at the place in a program
where you want to handle the problem. The catch keyword indicates the catching of an
exception.

Finally:​The finally block is used to execute a given set of statements, whether an exception is
 thrown or not thrown. For example, if you open a file, it must be closed whether an exception is
raised or not.

Example:

using System; class tryCatch { ​public static void Main() {​ ​int k=0; try
​ { ​int n=

10/k; Console.WriteLine(”n=”
​ + n); } ​catch(Exception e) {​ ​Console .WriteLine

(“Division By zero exception”); }​ ​Console.WriteLtne(”Statement executed

after Exception because of try catch”); }​

Q4. What is user-defined exception? Explain with

example.
We have seen built-in exception classes however, we often like to raise an exception when the
business rule of our application gets violated. So, for this we can create a custom exception
class by deriving Exception or ApplicationException class.

66 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

For example, create InvalidStudentNameException class in a school application, which does not allow
any special character or numeric value in a name of any of the students.

class Student {
public int StudentID { get; set; } public string

StudentName { get; set; } } ​class

InvalidStudentNameException : Exception {​
public InvalidStudentNameException()
{}

public InvalidStudentNameException(string
name)
: base(String.Format("Invalid Student Name: {0}",

name)){ } } ​class Program {​

static void Main(string[] args)
{
 Student newStudent = null;

try {
newStudent = new Student();
newStudent.StudentName =
"James007";

ValidateStudent(newStudent); }
catch(InvalidStudentNameException
ex) {
Console.WriteLine(ex.Message );
}

Console.ReadKey()
;}

private static void ValidateStudent(Student

std) {
Regex regex = new
Regex("^[a-zA-Z]+$");

if (!regex.IsMatch(std.StudentName))
throw new
InvalidStudentNameException(std.StudentName); } }

Q5. What is state management? Explain Application state

management
A web application is stateless. That means that a new instance of a page is created every time
when we make a request to the server to get the page and after the round trip our page has
been lost immediately. It only happens because of one server, all the controls of the Web Page
are created and after the round trip the server destroys all the instances. So, to retain the values
of the controls we use state management techniques.

67 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

State Management
Techniques

They are classified into the following 2

categories:
 Application State:

▪ If the information that we want to be accessed or stored globally throughout the application, even if
multiple users access the site or application at the same time, then we can use an Application
Object for such purposes.
▪ It stores information as a Dictionary Collection in key - value pairs. This value is accessible across
the pages of the application / website.
▪ There are 3 events of the Application which are as follows

Application_Start
Application_Error
Application_End

Example - Just for an example, I am setting the Page title in the Application Start event of the
Global.asax file. Code for setting value to the Application Object - "PageTitle" is the Key and
"Welcome to State Management Application" is the value.

Code for reading value from the Application Object

Q6. What is Query String? Explain encoding and decoding of
Query string

▪ Query String is the most simple and efficient way of maintaining information across
requests.
▪ The information we want to maintain will be sent along with the URL. A typical URL with a query
string looks like ​www.somewebsite.com/search.aspx?query=foo
▪ The URL part which comes after the? Symbol is called a
QueryString.

68 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ QueryString has two parts, a key and a value. In the above example, ​query ​is the key and ​foo ​is
its value.
▪ We can send multiple values through querystring, separated by the & symbol. The following code
shows sending multiple values to the foo.aspx page.

Response.Redirect("foo.aspx?id=1&name=fo
o");

▪ ​The following code shows reading the QueryString values in

foo.aspx

String id = Request.QueryString["id"];
String name =
Request.QueryString["name"];

▪ The ​HtmlEncode() ​method is particularly useful if you’re retrieving values from a database and
you aren’t sure if the text is valid HTML.
▪ We can use the ​HtmlDecode() ​method to revert the text to its normal form if we need to perform
additional operations or comparisons with it in your code.
▪ The ​UrlEncode() ​method changes text into a form that can be used in a URL, escaping spaces
and other special characters. This step is usually performed with information we want to add to the
query string. ​Label1.Text = Server.HtmlEncode("To bold text use the <b> tag."); Advantages
 ▪ Query string is lightweight and will not consume any server
resources.
▪ It is very easy to use, and it is the most efficient state management technique. However, it has
many ​Disadvantages

▪ We can pass information only as a string.

▪ URL length has limitations. So, we can't send much information through
URL.
▪ Information passed is clearly visible to everyone and can be easily
altered.

Q7. Role of Cookies in

ASP.NET

▪ A cookie is a small piece of information stored on the client machine. This file is located on client
machines "C:\Document and Settings\Currently_Login user\Cookie" path.
▪ It is used to store user preference information like Username, Password, City and Phone No etc.
on client machines. We need to import namespace called Systen.Web.HttpCookie before we use
cookie. ​Types of Cookies:

Persist Cookie - A cookie has not had expired time which is called as Persist
Cookie

Non-Persist Cookie - A cookie has expired time which is called as Non-Persist

Cookie

Creation of cookies:

It’s really easy to create a cookie in the Asp.Net with help of Response object or
HttpCookie

Example 1:

HttpCookie userInfo = new

HttpCookie("userInfo"); userInfo["UserName"] =
"Annathurai"; userInfo["UserColor"] = "Black";
userInfo.Expires.Add(new TimeSpan(0, 1, 0));
Response.Cookies.Add(userInfo);

Example 2:
 Response.Cookies["userName"].Value =
"Annathurai";

69 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Response.Cookies["userColor"].Value =
"Black";

Retrieve from cookie

Its easy way to retrieve cookie value form cookes by help of Request
object.

Example 1:

string User_Name = string.Empty; string

User_Color = string.Empty; User_Name =
Request.Cookies["userName"].Value; User_Color
= Request.Cookies["userColor"].Value;

Example 2:

string User_name = string.Empty;

string User_color = string.Empty;
HttpCookie reqCookies =
Request.Cookies["userInfo"]; if (reqCookies != null)
{
User_name = reqCookies["UserName"].ToString();
User_color = reqCookies["UserColor"].ToString(); }

When we make request from client to web server, the web server process the request and give
the lot of information with big pockets which will have Header information, Metadata, cookies
etc., Then repose object can do all the things with browser.

Cookie's common
property:

Domain​: This is used to associate cookies to domain.

Secure​: We can enable secure cookie to set true
(HTTPs). ​Value​: We can manipulate individual cookie.
Values​: We can manipulate cookies with key/value
pair. ​Expires​: Which is used to set expire date for the
cookies.
 Advantages of
Cookie:

▪ Its clear text so user can able to read it.

▪ We can store user preference information on the client machine.
▪ Its easy way to maintain.
▪ Fast accessing.

Disadvantages of
Cookie

▪ If user clears cookie information we can't get it back.

▪ No security.
▪ Each request will have cookie information with page.

Q8. Write a program to create a new cookie with the name “Username” and add it to the
HttpResponse object on the click of a button. Set the expiry date of the cookie to One year
from Now.

protected void Button1_Click(object sender, EventArgs e) {

HttpCookie Username = new HttpCookie("UserName",

"WELCOME"); Username.Expires=DateTime.Now.AddYears(1);
​
Response.Cookies.Add(Username); }

Q9. Significant of ViewState in

ASP.NET

70 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

View State

▪ View State is the method to preserve the Value of the Page and Controls between round trips. It is
a Page-Level State Management technique.
▪ View State is turned on by default and normally serializes the data in every control on the page
regardless of whether it is actually used during a post-back.

Features of View State

These are the main features of view

state:
▪ Retains the value of the Control after post-back without using a
session.
▪ Stores the value of Pages and Control Properties defined in the
page.
▪ Creates a custom View State Provider that lets you store View State Information in a SQL
Server Database or in another data store.

Advantages of View
State

▪ Easy to Implement.
▪ No server resources are required: The View State is contained in a structure within the page
load.
▪ Enhanced security features: It can be encoded and compressed or Unicode
implementation.

Disadvantages of View
State

▪ ​Security Risk: ​The Information of View State can be seen in the page output source directly. We
can manually encrypt and decrypt the contents of a Hidden Field, but It requires extra coding. If
security is a concern, then consider using a Server-Based State Mechanism so that no sensitive
information is sent to the client.
▪ ​Performance: ​Performance is not good if we use a large amount of data because View State is
stored in the page itself and storing a large value can cause the page to be slow.
▪ ​Device limitation: ​Mobile Devices might not have the memory capacity to store a large
amount of View State data.
▪ It can store values for the same page only.
Example:

If we want to add one variable in View

State, ​ViewState["Var"]=Count; ​For
Retrieving information from View State
string Test=ViewState["TestVal"];

Q10. Difference between Application state and Session

state

▪ ASP.NET implements application state using the System.Web.HttpApplicationState

 class.
▪ It provides methods for storing information which can be accessed
globally.
▪ Information stored on application state will be available for all the users using the
website.
▪ Usage of application state is the same as
sessions.

The following code shows storing a value in an application variable and reading
from it.

Application["pageTitle"] = "Welcome to my website

- "; String pageTitle; if (Application["pageTitle"] !=
null) pageTitle =
Application["pageTitle"].ToString();

We should get a basic knowledge about the events associated with application and
session.

71 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

These events can be seen in the ​global.asax
file.

▪ ​Application_Start ​This event executes when application initializes. This will execute when
ASP.NET worker process recycles and starts again.
▪ ​Application_End ​Executes when the application
ends.
▪ ​Session_Start ​Executes when a new session
starts.
▪ ​Session_End ​Executes when session ends. Note: this event will be fired only if you are using
InProc as session mode.

Example

The most common usage of application variables is to count the active number of visitors
that are browsing currently.

The following code shows how this is

done​.
 void Application_Start(object sender, EventArgs

e) { ​// Application started - Initializing to 0

Application["activeVisitors"] = 0; } ​void

Session_Start(object sender, EventArgs e) {​ ​if

(Application["activeVisitors"] != null) {​

Application.Lock(); int
​ visitorCount =
(int)Application["activeVisitors"];
Application["activeVisitors"] = visitorCount++;

Application.UnLock(); } ​}

▪ Data stored in session will be kept in server memory and it is protected as it will never get
transmitted to a client.
▪ Every client that uses the application will have separate sessions. Session state is ideal for storing
user specific information.

The following code shows storing a string value in

session.

Session["name"] = "Value"; Values stored in sessions can be removed by several methods.

Session.Abandon() : Cancels the session and fires end event. This is used when you are done
with the session. Session.Clear() /Session.RemoveAll() : Clears all contents of the session. This
will not end the session Session.Remove(string) : Removes the session name supplied.

Working of
Session:
▪ ASP.NET maintains a unique id which is called as "session id" for each session. This id is
generated using a custom algorithm and it is unique always.

▪ Session id will be sent to the client as a cookie and the browser resends this upon each
request.
▪ ASP.NET uses this session id to identify the session
object.

string sessionId =
Session.SessionID
 Session State
▪ Session state is user and browser specific.

72 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ Session state can be stored in memory on the server as well as client's
cookies.
▪ If client has disabled cookies in his browser then session state will be stored in
URL.
▪ Session state has scope to the current browser only. If we change the browser session id is
changed.

Application State
▪ Application state is application specific.
▪ Application state is stored only in the memory on the server.
▪ Application state does not track client's cookies or URL.
▪ Application state has no scope to the current browser. If we change the browser application
id remains same.

Q11. Explain the different types of CSS present in

ASP.NET.

There are three types of CSS as

follows:

▪ ​External CSS
▪ ​Internal CSS or Embedded
CSS
▪ ​Inline CSS

External Style Sheet ​The first way to add CSS style sheets to your web pages is through the
<link> ​element that points to an external CSS file.

For example the following <link> shows what options you have when embedding a style sheet in
your page:

<link href=”StyleSheet.css” rel=”Stylesheet” type=”text/css” media=”screen” />

The href property points to a file within our site when we create links between two pages. The rel
and type attributes tell the browser that the linked file is in fact a cascading style sheet. The
media attribute enables us to target different devices, including the screen, printer, and handheld
 devices. The default for the media attribute is screen, so it’s OK.

Embedded style sheet ​The second way to include style sheets is using embedded <style>
elements. The <style> element should be placed at the top of your ASPX or HTML page,
between the <head> tags.

For example, to change the appearance of an <h1> element in the current page alone, we can
add the following code to the <head> of our page:

<head runat=”server”>
<style type=”text/css”> h1

{ ​color: Blue; }​ ​</style>

</head>

Inline style sheet ​The third way to apply CSS to your HTML elements is to use inline styles.
Because the style attribute is already applied to a specific HTML element, we don’t need a
selector and we can write the declaration in the attribute directly:

<span style=”color: White; background-color: Black ;”>

This is white text on a black background. </span>

Q12. Explain the four most important selectors present

in CSS.

73 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Universal Selector ​The Universal selector, indicated by an asterisk (*), applies to all elements
in your page. The Universal selector can be used to set global settings like a font family. The
following rule set changes the font for all elements in our page to Arial: ​*{ ​font-family: Arial; }​

Type Selector The

​ Type selector enables us to point to an HTML element of a specific type.

With a Type selector all HTML elements of that type will be styled accordingly. ​h1 { ​color: Green;

} ​This Type selector now applies to all <h1> elements in your code and gives them a green

color. Type Selectors

​ are not case sensitive, so you can use both h1 and H1 to refer to the same
heading.

ID Selector ​The ID selector is always prefixed by a hash symbol (#) and enables us to refer to a
single element in the page. Within an HTML or ASPX page, we can give an element a unique ID
using the id attribute. With the ID selector, we can change the behavior for that single element,
for example:
 #IntroText {

font-style: italic;

} ​Because we can reuse this ID across multiple pages in our site (it only must be unique within a

single page),
​ you can use this rule to quickly change the appearance of an element that you use
once per page, but more than once in our site, for example with the following HTML code:

<p id=”IntroText”>I am italic because I have the right ID. </p>

Class Selector

The Class selector enables us to style multiple HTML elements through the class attribute. This
is handy when we want to give the same type of formatting to several unrelated HTML elements.
The following rule changes the text to red and bold for all HTML elements that have their class
attributes set to highlight:

.Highlight { ​font-weight: bold; color:

​ Red; } ​The following code snippet uses the Highlight class to

make the contents of a <span> element and a link​ (<a>) appear with a bold typeface: This is
normal text but <span class=”Highlight”>this is Red and Bold.</span> This is also normal text
but <a href=”CssDemo.aspx” class=”Highlight”>this link is Red and Bold as well.</a>

Q13. Explain <LINK> tag with

example.

▪ The HTML <link> tag is used for defining a link to an external document. It is placed in the
<head> section of the document.

74 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ The <link> tag defines a link between a document and an external
resource.
▪ The <link> tag is used to link to external style
sheets.

Syntax: ​<head><link rel="stylesheet" type="text/css"

href="theme.css"></head

Example: ​<html> <head> <title>HTML link Tag</title> <link rel="stylesheet"

type="text/css" href="default.css" /> </head> <body> <div> <p>Welcome to
our website. We provide tutorials on various subjects.</p> </div> </body>
 </html>

Where,
▪ ​rel​-can be used to specify the relationship of the target of the link to the current page.
▪ type-This attribute Provides information about the content type of the destination resource, telling
wether it's an HTML document, a JPG image, an Excel document, etc.
▪ ​href​(uri)-The "href" attribute specifies the destination resource, which the element is linking to. It may
specify a resource in the same website or in an external one.

Q14. What is Theme? How to create and use theme in ASP.NET

page.

A theme decides the look and feel of the website. It is a collection of files that define the looks of
a page. It can include skin files, CSS files & images.

We define themes in a special ​App_Themes ​folder. Inside this folder is one or more subfolders
named Theme1, Theme2 etc. that define the actual themes. The theme property is applied late in
the page's life cycle, effectively overriding any customization we may have for individual controls on
our page. There are 3 different options to apply themes to our website: 1​ . ​Setting the theme at the
page level: The Theme attribute is added to the page directive of the page.

<%​@​Page​Language​="C#"​AutoEventWireup​="true"​CodeFile​="Default.aspx.cs"​Inherits​="Default"​T
heme​="Theme1"​%>

2. ​Setting the theme at the site level: to set the theme for the entire website we can set the theme
in
the web.config of the website. Open the web.config file and locate the <pages> element and
add the theme attribute to it: ​<​pages​theme​="Theme1"> .... .... <​/pages​>

3. ​Setting
the theme programmatically at runtime: here the theme is set at runtime through coding.
It should be applied earlier in the page's life cycle ie. Page_PreInit event should be handled for
setting the theme. The better option is to apply this to the Base page class of the site as every
page in the site inherits from this class.

Page.Theme = Theme1; ​Uses

of Themes

75 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

1. Since themes can contain CSS files, images and skins, you can change colors, fonts, positioning
and images simply by applying the desired themes. 2. We can have as many themes as we want, and we
can switch between them by setting a single
attribute in the web.config file or an individual aspx page. Also, we can switch between themes programmatically. 3.
Setting the themes programmatically, we are offering our users a quick and easy way to change
the page to their likings. 4. Themes allow us to improve the usability of our site by giving users with
vision problems the
option to select a high contrast theme with a large font size.

Q15. What is Skin file? How to use

it.
ASP.Net skins can only be used to apply the styles to the ASP.Net controls.so in this article let us see the
procedure for using ASP.Net Skins. ​First create the web application as in the following:
1. ​"Start" - "All Programs" - "Microsoft Visual Studio 2010" ​2. ​"File" - "New Website" - "C# - Empty website" (to
avoid adding a master page) ​3. P ​ rovide the web site a name, such as UsingSkins or whatever you wish and
​ hen right-click on the solution in the Solution Explorer then select "Add New Item" -
specify the location ​4. T
"Default.aspx page" .

Add an ASP.Net Themes Folder ​To use the themes in the web site, we need to add an ASP.Net Themes
folder by right-clicking on Solution Explorer as in the following:

After adding the theme folder, add the SkinFile.skin file by right-clicking on the ASP.Net theme folder. The Solution
Explorer will then look as follows:
 Now add the ASP.Net controls inside the SkinFile.Skin and assign the Style to the controls using

76 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

their properties as in the following:

1. A control Id cannot be assigned to ASP.Net controls inside the SkinFile.skin. 2. SkinId must be assigned to the
ASP.Net controls inside the SkinFile.skin. 3. The SkinId should be uniquely defined because duplicate SkinId's per
control type are not allowed
in the same theme. 4. Only one default control skin per control type is allowed in
the same theme.

To use existing ASP.Net Skins in an ASP.Net page we need to assign the existing theme at page level as in the
following.
 In the preceding source code, we are assigning the existing ASP.Net Skin File at page level, the existing ASP.Net
Skin automatically appears in the box after using the Themes property in the page header. ​Assigning the Skin
to the ASP.Net Controls ​to assign the skin to the ASP.Net controls, you need to assign it to the control's SkinId
Property as in the following:

Q16. Role of Master Page in

ASP.NET

▪ ASP.NET master pages allow us to create a consistent layout for the pages in our
application.
▪ A single master page defines the look and feel and standard behavior that we want for all of the
pages (or a group of pages) in our application.
▪ We can then create individual content pages that contain the content we want to
display.
▪ When users request the content pages, they merge with the master page to produce output that
combines the layout of the master page with the content from the content page.
▪ Master pages actually consist of two pieces, the master page itself and one or more content
pages.
77 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

Use of Master Pages ​The master pages can be used to

accomplish the following:

Creating a set of controls that are common across all the web pages and attaching them to
all the web pages.

▪ A centralized way to change the above created set of controls which will effectively change all the
web pages.
▪ To some extent, a master page looks like a normal ASPX
page.
▪ It contains static HTML such as the <html>, <head>, and <body> elements, and it can also
contain other HTML and ASP.NET server controls.
▪ Inside the master page, you set up the markup that you want to repeat on every page, like the
general structure of the page and the menu.
▪ However, a master page is not a true ASPX page and cannot be requested in the browser directly
it only serves as the template that real web pages called content pages
▪ One difference is that while web forms start with the Page directive, a master page starts with a
Master directive that specifies the same information, as shown here
Q17. Explain relation between content page and master
page

▪ Master page provides a framework (common content as well as the layout) within which the
content from other pages can be displayed.
▪ It provides elements such as headers, footers, style definitions, or navigation bars that are
common to all pages in your web site.
▪ So the Content Pages need not have to duplicate code for shared elements within your Web
site.
▪ It gives a consistent look and feel for all pages in your
application.
▪ The master page layout consists of regions where the content from each content page should be
displayed.
▪ These regions can be set using ContentPlaceHolder server
controls.
▪ These are the regions where you are going to have dynamic content in your
page

78 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271

▪ A derived page also known as a content page is simply a collection of blocks the runtime will use
to fill the regions in the master.
▪ To provide content for a ContentPlaceHolder, you use another specialized control, called
Content.
▪ The ContentPlaceHolder control and the Content control have a one-to-one
relationship.
▪ For each ContentPlaceHolder in the master page, the content page supplies a matching Content
control
▪ ASP.NET links the Content control to the appropriate ContentPlaceHolder by matching the ID of
the ContentPlaceHolder with the Content ContentPlaceHolderID property of the corresponding
Content control.
79 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271
 Unit-IV
Topics:

ADO.NET Fundamentals| Data Binding|

Data Controls
80 ​| Salvi College Prof: Sonu Raj |sonuraj681@gmail.com | 8080837038 |8976249271