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        public void SendMouseClick(Process proc, Point location)
        {
            // this private method sends mouse clicks to a given point location
            // get the process' window handle
            IntPtr hWnd = GetWindowHandle(proc);
            // store the handle and process in a HandleRef
            HandleRef hRef = new HandleRef(proc, hWnd);
            // send the MouseButtonDown message using SendMessage
            win32API.SendMessage(hRef, System.Convert.ToUInt32(win32API.WM_Cmd.WM_LBUTTONDOWN), IntPtr.Zero, (IntPtr)(((location.Y * 0X10000) + location.X)));
            // sleep a bit
            System.Threading.Thread.Sleep(50);
            // send the MouseButtonUp message using SendMessage
            win32API.SendMessage(hRef, System.Convert.ToUInt32(win32API.WM_Cmd.WM_LBUTTONUP), IntPtr.Zero, (IntPtr)(((location.Y * 0X10000) + location.X)));					

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SendMessage(HWND, WM_LBUTTONDOWN, MK_LBUTTON, (((location.Y * 0X10000) + location.X)));
SendMessage(HWND, WM_LBUTTONUP, MK_LBUTTON, (((location.Y * 0X10000) + location.X)));