C#: Is there a way to properly convert Keys.Oem? to proper string without doing string manipulation?

Question

C#: Is there a method to convert Keys.Oem? to proper string without doing string manipulation?

When I do e.ToString() and if the key is a / or <, and so on, it converts as OemSlash, OemQuestion. Is there a way .net method properly convert Keys.OemSpace to "Space" without it including "OemSpace" and without string manipulation? And if there's not a built-in method to do such a thing, what would be the best way to go upon it then?

Answer 1

The only way I can think of to do this is to use regular expressions. I know this isn't the answer you probably wanted. Hopefully someone knows of a method to do this.

Answer 2

You probably want to use the ToAscii or ToUnicode function for this, which is part of the Win32 API. (I doubt you're going to get a simple pure BCL/cross-platform solution, if that's what you want.) They're relatively simple functions that convert virtual key codes to characters (either in ASCII or Unicode encoding, as the names suggest).

Edit: I think you may actually be in luck with the KeysConverter class!

Answer 3

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.OemQuestion, Keys.ShiftKey); // = '?'

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