only numbers in textbox

[Guest]

Hello,
how can i do this:
i have textbox, but i want that only numbers is possible to write in this
text box.

Thanks Lubos

 

[Lebesgue]

attach handler to Validating event. Use regular expression to validate
textbox content. Cancel the event if the content does not match "only
numbers"
pseudo code written here:

private void TextBox1_Validating(object sender, CancelEventArgs e)
{
TextBox tb = (TextBox)sender;
e.Cancel = !Regex.IsMatch(tb.Text, "[0-9]*");
}