Why is my Registered Hotkey not triggered when pressing the hotkey combination

Question

I've implemented the user32.dll register and unregister hot key methods, but after registering a hotkey, I never get the WndProc message 0x0312 when pressing the hotkey. Can someone review my code and help me understand why I never get the 0x0312 message.

The combination of hotkeys I've tried so far:

• Ctrl + Shift + F12
• F12
• F9

My implementation is just the most common implementation:

[DllImport("c:\\windows\\system32\\user32.dll")]
public static extern bool RegisterHotKey(IntPtr hWnd, int id, int fsModifiers, int vlc);
[DllImport("c:\\windows\\system32\\user32.dll")]
public static extern bool UnregisterHotKey(IntPtr hWnd, int id);

protected override void WndProc(ref Message m) {
    if(m.Msg == 0x0312) {
        int id = m.WParam.ToInt32();
        switch(id) {
            case 0:
                MessageBox.Show("Ctrl + Shift + F12 HotKey Pressed ! Do something here ... ");
                break;
        }
    }
}

I created a singleton class to handle the registration and unregistration of hotkeys:

public class HotKeyHandler {

    //Hotkey register and unregister.
    [DllImport("c:\\windows\\system32\\user32.dll")]
    public static extern bool RegisterHotKey(IntPtr hWnd, int id, int fsModifiers, int vlc);
    [DllImport("c:\\windows\\system32\\user32.dll")]
    public static extern bool UnregisterHotKey(IntPtr hWnd, int id);

    public const int MOD_ALT = 0x0001;
    public const int MOD_CONTROL = 0x0002;
    public const int MOD_SHIFT = 0x0004;
    public const int MOD_WIN = 0x0008;

    byte ID = 0;

    /// <summary>
    /// Keep the constructor private due to singleton implementation
    /// </summary>
    private HotKeyHandler() { }
    public static HotKeyHandler Instance = new HotKeyHandler();

    public bool RegisterHotKey(IntPtr handle, int modifier, Key key) {
        bool returnVal = RegisterHotKey(handle, ID, modifier, (int) key);
        ID++;
        return returnVal;
    }

    public void UnregisterAllHotKeys(IntPtr handle) {
        for(short s = 0; s <= ID; s++) {
            UnregisterHotKey(handle, s);
        }
    }
}

Finally I register the HotKey like this:

HotKeyHandler.Instance.RegisterHotKey(this.Handle, HotKeyHandler.MOD_CONTROL | HotKeyHandler.MOD_SHIFT, Key.F12);

Answer 1

I'd like to take the time to answer my own question just in case others might find themselves in the same.. rather irritating situation..

So after some digging and prodding I finally found out what was the problem, I was looking at the value for the Key ID that was passed to the RegisterHotKey method and noticed that the value I got did not match with the actual ID for the Key.
Turns out there exists two types of Key enums, there is the System.Windows.Input.Keyand the System.Windows.Forms.Keys. I was not aware of this and was using Input.Key which has different values from Forms.Keys

TL:DR
Use Forms.Keys for RegisterHotKey() and not Input.Key