[DllImport("user32", CharSet = CharSet.Ansi)]
		private extern static void mouse_event (int dwFlags, int dx, int dy, int _
  cButtons, int dwExtraInfo); 
 
private void PerformClick(int x, int y)
		{
			Point oldPos = System.Windows.Forms.Cursor.Position;
			System.Windows.Forms.Cursor.Position = new Point(x, y);
			// Normalisierte Koordinaten umrechnen
			// mouse_event benutzt Koordinaten von 0..65535
			int x1 = (65535 / Screen.PrimaryScreen.Bounds.Width);
			int y1 = (65535 / Screen.PrimaryScreen.Bounds.Height);
			x1 = x1 * x;
			y1 = y1 * y;
			mouse_event(2 | 0x8000, x1, y1, 0, 0);
			mouse_event(4 | 0x8000, x1, y1, 0, 0);
			System.Windows.Forms.Cursor.Position = oldPos;
		}