C# 全局热键设置 与 窗体热键设置

        private void FrmMain_KeyDown(object sender, KeyEventArgs e)

        {
            if (e.Alt && e.Shift && e.Control && e.KeyCode == Keys.S)
            {
                MessageBox.Show("我按了Control +Shift +Alt +S");
            }
        }

  public class AppHotKey
    {
        [DllImport("kernel32.dll")]
        public static extern uint GetLastError();
        //如果函数执行成功，返回值不为0。
        //如果函数执行失败，返回值为0。要得到扩展错误信息，调用GetLastError。
        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool RegisterHotKey(
            IntPtr hWnd,                //要定义热键的窗口的句柄
            int id,                     //定义热键ID（不能与其它ID重复）           
            KeyModifiers fsModifiers,   //标识热键是否在按Alt、Ctrl、Shift、Windows等键时才会生效
            Keys vk                     //定义热键的内容
            );

        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool UnregisterHotKey(
            IntPtr hWnd,                //要取消热键的窗口的句柄
            int id                      //要取消热键的ID
            );

        //定义了辅助键的名称（将数字转变为字符以便于记忆，也可去除此枚举而直接使用数值）
        [Flags()]
        public enum KeyModifiers
        {
            None = 0,
            Alt = 1,
            Ctrl = 2,
            Shift = 4,
            WindowsKey = 8
        }
        /// <summary>
        /// 注册热键
        /// </summary>
        /// <param name="hwnd">窗口句柄</param>
        /// <param name="hotKey_id">热键ID</param>
        /// <param name="keyModifiers">组合键</param>
        /// <param name="key">热键</param>
        public static void RegKey(IntPtr hwnd, int hotKey_id, KeyModifiers keyModifiers, Keys key)
        {
            try
            {
                if (!RegisterHotKey(hwnd, hotKey_id, keyModifiers, key))
                {
                    if (Marshal.GetLastWin32Error() == 1409) { MessageBox.Show("热键被占用 ！"); }
                    else
                    {
                        MessageBox.Show("注册热键失败！");
                    }
                }
            }
            catch (Exception) { }
        }
        /// <summary>
        /// 注销热键
        /// </summary>
        /// <param name="hwnd">窗口句柄</param>
        /// <param name="hotKey_id">热键ID</param>
        public static void UnRegKey(IntPtr hwnd, int hotKey_id)
        {
            //注销Id号为hotKey_id的热键设定
            UnregisterHotKey(hwnd, hotKey_id);
        }
    }

 　　    private const int WM_HOTKEY = 0x312; //窗口消息-热键
        private const int WM_CREATE = 0x1; //窗口消息-创建
        private const int WM_DESTROY = 0x2; //窗口消息-销毁
        private const int Space = 0x3572; //热键ID
        protected override void WndProc(ref Message m)
        {
            base.WndProc(ref m);
            switch (m.Msg)
            {
                case WM_HOTKEY: //窗口消息-热键ID
                    switch (m.WParam.ToInt32())
                    {
                        case Space: //热键ID
                            MessageBox.Show("我按了Control +Shift +Alt +S");
                            break;
                        default:
                            break;
                    }
                    break;
                case WM_CREATE: //窗口消息-创建
                    AppHotKey.RegKey(Handle, Space, AppHotKey.KeyModifiers.Ctrl | AppHotKey.KeyModifiers.Shift | AppHotKey.KeyModifiers.Alt, Keys.S);
                    break;
                case WM_DESTROY: //窗口消息-销毁
                    AppHotKey.UnRegKey(Handle, Space); //销毁热键
                    break;
                default:
                    break;
            }
        }