public static extern bool DispatchMessage(ref MSG msg);
 public static extern bool TranslateMessage(ref MSG msg);
 public static extern bool PeekMessage(ref MSG msg, int hWnd, uint wFilterMin, uint wFilterMax, uint wFlag);
 public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, ref MSG lParam );
 public static extern bool GetMessage(ref MSG msg, int hWnd, uint wFilterMin, uint wFilterMax);