`Button`

When a user clicks on a button, something happens. This is key to the design of many programs. In Windows Forms, we have access to the handy Button control.

Please open a new Windows Forms project based on the VB.NET language. Next, locate the Toolbox panel and drag the Button icon to your form.

Code example

Next, double-click on the button in the designer view. Visual Studio will generate a Button1_Click event handler. We can add some VB.NET code here.

Detail We use the Enabled property on the Button. If the variable "x" is less than 10, the button remains enabled.

Tip When the button is clicked, the Button1_Click event handler is executed. The title of the Window is changed to equal the click count.

Public Class Form1

    Dim x As Integer

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        ' Increment local variable and change window title.
        x += 1
        Me.Text = x.ToString()

        ' If number is less than 10, it is still enabled.
        ' ... At 10, disable the button.
        Button1.Enabled = x < 10
    End Sub

End Class

Expressions

This program shows how to use expressions to control interface elements. The Enabled property is assigned True or False based on an expression.

And It is true when the variable "x" is less than 10. So the button remains enabled.

But When the "x" reaches 10, the button is disabled. Enabled is set to false.

Tip Using expressions eliminates the need to use if-statements. Often, this simplifies programs and makes them easier to understand.

The Click event handler is often used with Buttons. And the Enabled property, available on most Windows Forms controls, is also useful.