VB.NET Technology

For creating a new project you need to first load Visual Studio .NET and select Windows Application as in Figure below . Type the name of the project below along with selecting the desired location to store your files.

Designing The Interface

We are going to design a simple application for adding values in List Box from from textbox input by the user, for this will need to add the following items onto your form.

• GroupBox
• Label
• ComboBox
• Textbox
• Button
• ListBox

Adding The Code : When this form loads we need to populate the ComboBox with the appropriate values. Add the following code by clicking on the form on the outside of the groupBox. You should see something like this:

write this code on Form Load Event

Private Sub Form1_Load(sender As Object, e As EventArgs)
	comboBox1.Items.Add("Dr.")
	comboBox1.Items.Add("Er.")
	comboBox1.Items.Add("Mr.")
	comboBox1.Items.Add("Mrs.")
	comboBox1.Items.Add("Ms.")
	comboBox1.Focus()
End Sub

Double-click on the OK button and add the following code:

Private Sub button1_Click(sender As Object, e As EventArgs)
	listBox1.Items.Add((comboBox1.Text + " " + textBox1.Text & " ") + textBox2.Text)
	textBox1.Text = ""
	textBox2.Text = ""
	comboBox1.Text = ""
	comboBox1.Focus()
End Sub

When we want to allow the user to clear all fields entered into the listBox, we will need to go back like we did above to the visual designer and double-click on the Clear List button, this should again switch to a code view and allow you to add the following code-

Private Sub button2_Click(sender As Object, e As EventArgs)
	listBox1.Items.Clear()
	comboBox1.Focus()
End Sub

And finally we want to allow the user to be able to close the application when they want. To show you another way to allow the user to close the program aside from that catchy X in the upper right-hand corner, I have provided a button entitled Close.

Private Sub button3_Click(sender As Object, e As EventArgs)
	Me.Dispose()
End Sub

Controls

System.Windows.Forms.Control class This class defines the basic functionality of the controls, which is why many properties and events in the controls. Some controls, named custom or user controls, derive from another class: System.Windows.Forms.UserControl. This class is itself derived from the Control class and provides the functionality we need to create controls ourselves.

Properties

All controls have a number of properties that are used to manipulate the behavior of the control. The base class of most controls, Control, has a number of properties that other controls either inherit directly or override to provide some kind of custom behavior.

Events

When a user clicks a button or presses a button, you as the programmer of the application, want to be told that this has happened. To do so, controls use events. The Control class defines a number of events that are common to the controls we'll use in this chapter.