using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.ComponentModel;
public class MyHotKeys
{
    #region fields
    public const int WM_HOTKEY = 0x312;
    public const uint MOD_KEYUP = 0x1000;
    #endregion

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

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

    public static void RegisterHotKey(Form f, uint key)
    {
        Func ff = delegate()
        {
            if(!RegisterHotKey(f.Handle, (int)key, MOD_KEYUP, key))
            {
                Win32Exception w32e = new Win32Exception();
                MessageBox.Show(w32e.ToString());
            }
        };

        f.Invoke(ff); // this should be checked if we really need it (InvokeRequired), but it's faster this way
    }

    private delegate void Func();

    public static void UnregisterHotKey(Form f, int key)
    {
        try
        {
            Func ff = delegate()
            {
                UnregisterHotKey(f.Handle, key);
            };

            f.Invoke(ff); // this should be checked if we really need it (InvokeRequired), but it's faster this way
        }
        catch (Exception ex)
        {
            Debug.WriteLine(ex.ToString());
        }
    }
}

MyHotKeys.RegisterHotKey(this, VK_MEDIA_PLAY_PAUSE);
MyHotKeys.RegisterHotKey(this, VK_MEDIA_STOP);
MyHotKeys.RegisterHotKey(this, VK_MEDIA_PREV_TRACK);
MyHotKeys.RegisterHotKey(this, VK_MEDIA_NEXT_TRACK);