如何在。net应用程序中阻止Alt代码?

I have a .NET app with buttons which use numbers for mnemonics. (e.g. "&1 - Check" and "&2 - Cash") When I hit Alt+1, I expect the Check button to be clicked. This works when I use the standard number keys on a keyboard. However, when I hit Alt+1 using the number pad, Windows takes over and inserts the symbol that matches the "alt code" of 1. See I have a .NET app with buttons which use number