c# - How to consume Alt + Numpad using RawInput in c#?

Question

I am writing a class to consume 'ALL' input from barcode scanner. I am using the code from http://nicholas.piasecki.name/blog/2009/02/distinguishing-barcode-scanners-from-the-keyboard-in-winforms/

I've added following lines in PreFilterMessage() for testing.

if (m.Msg != Win32.WM_INPUT)
{
    // Allow any non WM_INPUT message to pass through
    return false;
}
return true;

The problem is with some barcode that has "═" (Alt + Numpad: 205) in it. and it gets typed in the textbox. How can I prevent the Alt + Numpad keys from dispatching?

I am able to handle this issue by catching the keys at form level, by setting the form

keypreview=true, 

and in form_keypress event setting

//if(Alt pressed && numpad keys)
e.Handled = true;

But ideally this should be handled by the class. Any ideas??

Answer 1

检查修饰键以阻止 Alt+Numpad 键怎么样？例如

if (ModifierKeys == Keys.Alt) return true;