//===========================================
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern void mouse_event(uint dwFlags, uint dx, uint dy, uint dwData, UIntPtr dwExtraInfo);
 
        [Flags]
        public enum MouseEventFlags : uint
        {
            LEFTDOWN = 0x00000002,
            LEFTUP = 0x00000004,
            MIDDLEDOWN = 0x00000020,
            MIDDLEUP = 0x00000040,
            MOVE = 0x00000001,
            ABSOLUTE = 0x00008000,
            RIGHTDOWN = 0x00000008,
            RIGHTUP = 0x00000010
        }

 public void DoMouseClick(uint X, uint Y)
        {
            mouse_event((uint)(MouseEventFlags.LEFTDOWN | MouseEventFlags.LEFTUP), X, Y, 0, UIntPtr.Zero);
        }