#1,077 – Checking for Single Modifer vs. Multiple Modifier Keys

In keypress events, you can check to see if the user is also holding down one of the modifier keys (Ctrl, Alt, Shift, or Windows key).  You do this by checking the KeyEventArgs.KeyboardDevice.Modifiers property.

You sometimes want to check to see if one and only one modifier key is being held down (e.g. Ctrl key without Alt, Shift, or Windows).  You do this by checking to see if the Modifiers property is equal to one of the ModifierKeys enumerated values.

            if ((e.Key == Key.G) &&
                (e.KeyboardDevice.Modifiers == ModifierKeys.Control))
                MessageBox.Show("Ctrl+G detected, NO Alt/Shift/Windows");

You may also want to check to see if the control key is being pressed, either alone or in conjunction with one of the other modifier keys.  You do this by using a mask.

            if ((e.Key == Key.G) &&
                ((e.KeyboardDevice.Modifiers & ModifierKeys.Control) == ModifierKeys.Control))
                MessageBox.Show("Ctrl+G or Ctrl+Alt+G, Ctrl+Alt+Windows+G, etc.");