How to disallow non-numeric letters in WinForms TextBox?

[jmcilhinney]

You could throw in a condition for your modifier keys if you want to use the other numbers

Or you could do as I said in post #8 and use KeyData instead of KeyCode. KeyData is the combination of current modifier keys and the key that was just depressed so if that is equal to just a digit or number pad key then you know that no modifier keys were depressed. That will then also exclude keys depressed with Ctrl, Alt or Ctrl+Alt as well.