Adding Menus and Sub Menus in an Application

Traditionally, the Menu, MainMenu, ContextMenu, and MenuItem classes

were used for adding menus, sub-menus and context menus in a Windows
application.

Now, the MenuStrip,

the ToolStripMenuItem, ToolStripDropDown andToolStripDropDown
Menu controls replace and add functionality to the Menu-related controls of
previous versions. However, the old control classes are retained for both
backward compatibility and future use.

Let us create a typical windows main menu bar and sub menus using the
old version controls first since these controls are still much used in old
applications.

Following is an example, which shows how we create a menu bar with menu
items: File, Edit, View and Project. The File menu has the sub menus New,
Open and Save.

Let's double click on the Form and put the following code in the opened
window.

Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'defining the main menu bar
Dim mnuBar As New MainMenu()
'defining the menu items for the main menu bar
Dim myMenuItemFile As New MenuItem("&File")
Dim myMenuItemEdit As New MenuItem("&Edit")
Dim myMenuItemView As New MenuItem("&View")
Dim myMenuItemProject As New MenuItem("&Project")

'adding the menu items to the main menu bar

mnuBar.MenuItems.Add(myMenuItemFile)
mnuBar.MenuItems.Add(myMenuItemEdit)
mnuBar.MenuItems.Add(myMenuItemView)
 mnuBar.MenuItems.Add(myMenuItemProject)

' defining some sub menus

Dim myMenuItemNew As New MenuItem("&New")
Dim myMenuItemOpen As New MenuItem("&Open")
Dim myMenuItemSave As New MenuItem("&Save")

'add sub menus to the File menu

myMenuItemFile.MenuItems.Add(myMenuItemNew)
myMenuItemFile.MenuItems.Add(myMenuItemOpen)
myMenuItemFile.MenuItems.Add(myMenuItemSave)

'add the main menu to the form

Me.Menu = mnuBar

' Set the caption bar text of the form.

Me.Text = "tutorialspoint.com"
End Sub
End Class

When the above code is executed and run using Start button available at
the Microsoft Visual Studio tool bar, it will show the following window:
Windows Forms contain a rich set of classes for creating your own custom
menus with modern appearance, look and feel.
The MenuStrip,ToolStripMenuItem, ContextMenuStrip controls are
used to create menu bars and context menus efficiently.

Click the following links to check their details:

S.N. Control & Description

1
MenuStrip

It provides a menu system for a form.

2 ToolStripMenuItem

It represents a selectable option displayed on

a MenuStrip orContextMenuStrip. The ToolStripMenuItem control
replaces and adds functionality to the MenuItem control of previous
versions.

2
ContextMenuStrip

It represents a shortcut menu.

Adding the Cut, Copy and Paste Functionalities

in a Form
The methods exposed by the ClipBoard class are used for adding the cut,
copy and paste functionalities in an application. The ClipBoard class
provides methods to place data on and retrieve data from the system
Clipboard.

It has the following commonly used methods:

S.N Method Name & Description

1
Clear

Removes all data from the Clipboard.

2 ContainsData

Indicates whether there is data on the Clipboard that is in the specified

format or can be converted to that format.

3
ContainsImage

Indicates whether there is data on the Clipboard that is in the Bitmap

format or can be converted to that format.

4 ContainsText

Indicates whether there is data on the Clipboard in the Text or UnicodeText

format, depending on the operating system.

5
GetData

Retrieves data from the Clipboard in the specified format.

6
GetDataObject

Retrieves the data that is currently on the system Clipboard.

7
GetImage

Retrieves an image from the Clipboard.

8
GetText

Retrieves text data from the Clipboard in the Text or UnicodeText format,
 depending on the operating system.

9 GetText(TextDataFormat)

Retrieves text data from the Clipboard in the format indicated by the
specified TextDataFormat value.

10
SetData

Clears the Clipboard and then adds data in the specified format.

11 SetText(String)

Clears the Clipboard and then adds text data in the Text or UnicodeText
format, depending on the operating system.

Following is an example, which shows how we cut, copy and paste data
using methods of the Clipboard class. Take the following steps:

Add a rich text box control and three button controls on the form.

Change the text property of the buttons to Cut, Copy and Paste, respectively.

Double click on the buttons to add the following code in the code editor:

Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) _
Handles MyBase.Load
' Set the caption bar text of the form.
Me.Text = "tutorialspoint.com"
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) _
Handles Button1.Click
Clipboard.SetDataObject(RichTextBox1.SelectedText)
RichTextBox1.SelectedText = ""
End Sub
 Private Sub Button2_Click(sender As Object, e As EventArgs) _
Handles Button2.Click
Clipboard.SetDataObject(RichTextBox1.SelectedText)
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) _
Handles Button3.Click
Dim iData As IDataObject
iData = Clipboard.GetDataObject()
If (iData.GetDataPresent(DataFormats.Text)) Then
RichTextBox1.SelectedText = iData.GetData(DataFormats.Text)
Else
RichTextBox1.SelectedText = " "
End If
End Sub
End Class

When the above code is executed and run using Start button available at
the Microsoft Visual Studio tool bar, it will show the following window:

Enter some text and check how the buttons work.

Anchoring and Docking Controls in a Form

Anchoring allows you to set an anchor position for a control to the edges
of its container control, for example, the form. The Anchor property of the
Control class allows you to set values of this property. The Anchor property
gets or sets the edges of the container to which a control is bound and
determines how a control is resized with its parent.

When you anchor a control to a form, the control maintains its distance
from the edges of the form and its anchored position, when the form is
resized.

You can set the Anchor property values of a control from the Properties
window:

For example, let us add a Button control on a form and set its anchor
property to Bottom, Right. Run this form to see the original position of the
Button control with respect to the form.
Now, when you stretch the form, the distance between the Button and the
bottom right corner of the form remains same.

Docking of a control means docking it to one of the edges of its container.

In docking, the control fills certain area of the container completely.

The Dock property of the Control class does this. The Dock property gets or
sets which control borders are docked to its parent control and determines
how a control is resized with its parent.

You can set the Dock property values of a control from the Properties
window:
For example, let us add a Button control on a form and set its Dock
property to Bottom. Run this form to see the original position of the Button
control with respect to the form.

Now, when you stretch the form, the Button resizes itself with the form.
Modal Forms
Modal Forms are those forms that need to be closed or hidden before you
can continue working with the rest of the application. All dialog boxes are
modal forms. A MessageBox is also a modal form.

You can call a modal form by two ways:

Calling the ShowDialog method

Calling the Show method

Let us take up an example in which we will create a modal form, a dialog

box. Take the following steps:

Add a form, Form1 to your application, and add two labels and a button control
to Form1

Change the text properties of the first label and the button to 'Welcome to
Tutorials Point' and 'Enter your Name', respectively. Keep the text properties of
the second label as blank.
 Add a new Windows Form, Form2, and add two buttons, one label, and a text
box to Form2.

Change the text properties of the buttons to OK and Cancel, respectively.

Change the text properties of the label to 'Enter your name:'.

Set the FormBorderStyle property of Form2 to FixedDialog, for giving it a dialog

box border.

Set the ControlBox property of Form2 to False.

Set the ShowInTaskbar property of Form2 to False.

Set the DialogResult property of the OK button to OK and the Cancel button to
Cancel.

Add the following code snippets in the Form2_Load method of Form2:

Private Sub Form2_Load(sender As Object, e As EventArgs) _
Handles MyBase.Load
AcceptButton = Button1
CancelButton = Button2
End Sub

Add the following code snippets in the Button1_Click method of Form1:

Private Sub Button1_Click(sender As Object, e As EventArgs) _

Handles Button1.Click
Dim frmSecond As Form2 = New Form2()
If frmSecond.ShowDialog() = DialogResult.OK Then
Label2.Text = frmSecond.TextBox1.Text
End If
End Sub

When the above code is executed and run using Start button available at
the Microsoft Visual Studio tool bar, it will show the following window:

Clicking on the 'Enter your Name' button displays the second form:
Clicking on the OK button takes the control and information back from the
modal form to the previous form:

VB.Net - Event Handling

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Events are basically a user action like key press, clicks, mouse movements,
etc., or some occurrence like system generated notifications. Applications
need to respond to events when they occur.
Clicking on a button, or entering some text in a text box, or clicking on a
menu item, all are examples of events. An event is an action that calls a
function or may cause another event.

Event handlers are functions that tell how to respond to an event.

VB.Net is an event-driven language. There are mainly two types of events:

Mouse events

Keyboard events

Handling Mouse Events

Mouse events occur with mouse movements in forms and controls.
Following are the various mouse events related with a Control class:

MouseDown - it occurs when a mouse button is pressed

MouseEnter - it occurs when the mouse pointer enters the control

MouseHover - it occurs when the mouse pointer hovers over the control

MouseLeave - it occurs when the mouse pointer leaves the control

MouseMove - it occurs when the mouse pointer moves over the control

MouseUp - it occurs when the mouse pointer is over the control and the mouse
button is released

MouseWheel - it occurs when the mouse wheel moves and the control has
focus

The event handlers of the mouse events get an argument of

typeMouseEventArgs. The MouseEventArgs object is used for handling
mouse events. It has the following properties:

Buttons - indicates the mouse button pressed

Clicks - indicates the number of clicks

 Delta - indicates the number of detents the mouse wheel rotated

X - indicates the x-coordinate of mouse click

Y - indicates the y-coordinate of mouse click

Example
Following is an example, which shows how to handle mouse events. Take
the following steps:

Add three labels, three text boxes and a button control in the form.

Change the text properties of the labels to - Customer ID, Name and Address,
respectively.

Change the name properties of the text boxes to txtID, txtName and txtAddress,
respectively.

Change the text property of the button to 'Submit'.

Add the following code in the code editor window:

Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
' Set the caption bar text of the form.
Me.Text = "tutorialspont.com"
End Sub

Private Sub txtID_MouseEnter(sender As Object, e As EventArgs)_

Handles txtID.MouseEnter
'code for handling mouse enter on ID textbox
txtID.BackColor = Color.CornflowerBlue
txtID.ForeColor = Color.White
End Sub
Private Sub txtID_MouseLeave(sender As Object, e As EventArgs) _
Handles txtID.MouseLeave
'code for handling mouse leave on ID textbox
 txtID.BackColor = Color.White
txtID.ForeColor = Color.Blue
End Sub
Private Sub txtName_MouseEnter(sender As Object, e As EventArgs) _
Handles txtName.MouseEnter
'code for handling mouse enter on Name textbox
txtName.BackColor = Color.CornflowerBlue
txtName.ForeColor = Color.White
End Sub
Private Sub txtName_MouseLeave(sender As Object, e As EventArgs) _
Handles txtName.MouseLeave
'code for handling mouse leave on Name textbox
txtName.BackColor = Color.White
txtName.ForeColor = Color.Blue
End Sub
Private Sub txtAddress_MouseEnter(sender As Object, e As EventArgs) _
Handles txtAddress.MouseEnter
'code for handling mouse enter on Address textbox
txtAddress.BackColor = Color.CornflowerBlue
txtAddress.ForeColor = Color.White
End Sub
Private Sub txtAddress_MouseLeave(sender As Object, e As EventArgs) _
Handles txtAddress.MouseLeave
'code for handling mouse leave on Address textbox
txtAddress.BackColor = Color.White
txtAddress.ForeColor = Color.Blue
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) _

Handles Button1.Click
MsgBox("Thank you " & txtName.Text & ", for your kind cooperation")
End Sub
End Class
When the above code is executed and run using Start button available at
the Microsoft Visual Studio tool bar, it will show the following window:

Try to enter text in the text boxes and check the mouse events:

Handling Keyboard Events

Following are the various keyboard events related with a Control class:

KeyDown - occurs when a key is pressed down and the control has focus
 KeyPress - occurs when a key is pressed and the control has focus

KeyUp - occurs when a key is released while the control has focus

The event handlers of the KeyDown and KeyUp events get an argument of
typeKeyEventArgs. This object has the following properties:

Alt - it indicates whether the ALT key is pressed/p>

Control - it indicates whether the CTRL key is pressed

Handled - it indicates whether the event is handled

KeyCode - stores the keyboard code for the event

KeyData - stores the keyboard data for the event

KeyValue - stores the keyboard value for the event

Modifiers - it indicates which modifier keys (Ctrl, Shift, and/or Alt) are pressed

Shift - it indicates if the Shift key is pressed

The event handlers of the KeyDown and KeyUp events get an argument of
typeKeyEventArgs. This object has the following properties:

Handled - indicates if the KeyPress event is handled

KeyChar - stores the character corresponding to the key pressed

Example
Let us continue with the previous example to show how to handle keyboard
events. The code will verify that the user enters some numbers for his
customer ID and age.

Add a label with text Property as 'Age' and add a corresponding text box named
txtAge.

Add the following codes for handling the KeyUP events of the text box txtID.

Private Sub txtID_KeyUP(sender As Object, e As KeyEventArgs) _

 Handles txtID.KeyUp

If (Not Char.IsNumber(ChrW(e.KeyCode))) Then

MessageBox.Show("Enter numbers for your Customer ID")

txtID.Text = " "

End If

End Sub

Add the following codes for handling the KeyUP events of the text box txtID.

Private Sub txtAge_KeyUP(sender As Object, e As KeyEventArgs) _

Handles txtAge.KeyUp

If (Not Char.IsNumber(ChrW(e.keyCode))) Then

MessageBox.Show("Enter numbers for age")

txtAge.Text = " "

End If

End Sub

When the above code is executed and run using Start button available at
the Microsoft Visual Studio tool bar, it will show the following window:
If you leave the text for age or ID as blank or enter some non-numeric
data, it gives a warning message box and clears the respective text: