DllImport

[DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

 

[DllImport("user32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);

 

[DllImport("user32.dll")]
private static extern bool SetCursorPos(int X, int Y);


[DllImport("user32.dll", EntryPoint = "mouse_event")]
private static extern int mouse_event(int dwFlags, int dx, int dy, int cButtons, int dwExtraInfo);

 

[DllImport("user32.dll", EntryPoint = "ShowWindow", SetLastError = true)]
private static extern bool ShowWindow(IntPtr hWnd, uint nCmdShow);

 

IntPtr hwnd = FindWindow(null, "Microsoft Excel");
ShowWindow(hwnd, 3);
SetForegroundWindow(hwnd);
SetCursorPos(500, 300);
mouse_event(6, 0, 0, 0, 0);