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. We use its Click event, and set its Enabled property.
Let us begin. 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. You may want to reposition it by dragging it around the window.
Next, create a Click event handler on your button. This can be done by double-clicking on the button in the designer view. Visual Studio will generate a Button1_Click event handler at this point.
Statements In the Click event handler, we can add some VB.NET code statements. Here, we access a field "x" on the Form1 class.
Enabled We use the Enabled property on the Button. If the variable "x" is less than 10, the button remains enabled.
When the button is clicked, the Button1_Click event handler is executed. The title of the Window is changed to equal the click count. And after ten clicks, the button is disabled.
Example Click event handler: VB.NET
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
Expressions. This program shows how to use expressions to control interface elements. The Enabled property is assigned True or False based on an expression. 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.
Summary. The Click event handler is important for the Button control. And the Enabled property, available on most Windows Forms controls, is also useful. We can execute any code when the user clicks. Most Windows Forms program include a button.