Validating a textbox control

In this application I’m validating a textbox by allowing only number to enter.

Create a windows application with a textbox control as shown in fig below.

Here what we do is add some code in keyPress event of the textbox control, which  will show a message when we enter a wrong data.Add the following code in the keyPress event of the textbox control

ValidateNumber(e.KeyChar) function is shown below

Run the project and enter an alphabet,it will show a message box as shown below