HotkeyManager.cs

// https://stackoverflow.com/questions/3568513/how-to-create-keyboard-shortcut-in-windows-that-call-function-in-my-app/3569097#3569097

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

public class HotKeyManager
{
    public static event EventHandler<HotKeyEventArgs> HotKeyPressed;

    public static int RegisterHotKey(Keys key, KeyModifiers modifiers)
    {
        int id = System.Threading.Interlocked.Increment(ref _id);
        RegisterHotKey(_wnd.Handle, id, (uint)modifiers, (uint)key);
        return id;
    }

    public static bool UnregisterHotKey(int id)
    {
        return UnregisterHotKey(_wnd.Handle, id);
    }

    protected static void OnHotKeyPressed(HotKeyEventArgs e)
    {
        if (HotKeyManager.HotKeyPressed != null)
        {
            HotKeyManager.HotKeyPressed(null, e);
        }
    }

    private static MessageWindow _wnd = new MessageWindow();

    private class MessageWindow : Form
    {
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_HOTKEY)
            {
                HotKeyEventArgs e = new HotKeyEventArgs(m.LParam);
                HotKeyManager.OnHotKeyPressed(e);
            }

            base.WndProc(ref m);
        }

        private const int WM_HOTKEY = 0x312;
    }

    [DllImport("user32")]
    private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);

    [DllImport("user32")]
    private static extern bool UnregisterHotKey(IntPtr hWnd, int id);

    private static int _id = 0;
}


public class HotKeyEventArgs : EventArgs
{
    public readonly Keys Key;
    public readonly KeyModifiers Modifiers;

    public HotKeyEventArgs(Keys key, KeyModifiers modifiers)
    {
        this.Key = key;
        this.Modifiers = modifiers;
    }

    public HotKeyEventArgs(IntPtr hotKeyParam)
    {
        uint param = (uint)hotKeyParam.ToInt64();
        Key = (Keys)((param & 0xffff0000) >> 16);
        Modifiers = (KeyModifiers)(param & 0x0000ffff);
    }
}

[Flags]
public enum KeyModifiers
{
    Alt = 1,
    Control = 2,
    Shift = 4,
    Windows = 8,
    NoRepeat = 0x4000
}