Question

If I know that a certain key has been pressed (eg Key.D3), and that the Shift key is also down (Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift)), how can I find out what character that refers to (eg, # on US keyboard, UK pound sign on UK keyboard, etc)?

Put another way, how can I find out, programatically, that Shift + 3 produces # (it wouldn’t on a non-US keyboard).

Answer 1

If you want to determine what character you will get from a given key with given modifiers, you should use the user32 ToAscii function. Or ToAsciiEx if you want to use a keyboard layout other then the current one.

using System.Runtime.InteropServices; public static class User32Interop {   public static char ToAscii(Keys key, Keys modifiers)   {     var outputBuilder = new StringBuilder(2);     int result = ToAscii((uint)key, 0, GetKeyState(modifiers),                          outputBuilder, 0);     if (result == 1)       return outputBuilder[0];     else       throw new Exception('Invalid key');   }    private const byte HighBit = 0x80;   private static byte[] GetKeyState(Keys modifiers)   {     var keyState = new byte[256];     foreach (Keys key in Enum.GetValues(typeof(Keys)))     {       if ((modifiers & key) == key)       {         keyState[(int)key] = HighBit;       }     }     return keyState;   }    [DllImport('user32.dll')]   private static extern int ToAscii(uint uVirtKey, uint uScanCode,                                     byte[] lpKeyState,                                     [Out] StringBuilder lpChar,                                     uint uFlags); } 

You can now use it like this:

char c = User32Interop.ToAscii(Keys.D3, Keys.ShiftKey); // = '#' 

If you need more than one modifier, just or them. Keys.ShiftKey | Keys.AltKey