Validation - I have textbox field as loan

Question

I ask a question i have textbox field as loan in that i want to type only numbers not charcters.

so you posted a answer as follows

 think you must register Key press or key down event in page load.
TextBox1.KeyDown += new KeyEventHandler(TextBox1_KeyDown);

but in vb.net not page load only form load.

in the above Textbox1_KeyDown.

_KeyDown it is not automatically come.

wat to do help me.please send any other code.

creating the above application using vb.net with csharp code.

it is a window application.please help me.it is urgent.