public void ScrollDownEvent(Point point) { int x = point.X; int y = point.Y; WindowsAPI.ClientToScreen(handle, ref point); int xScreenPos = point.X; int yScreenPos = point.Y; int delta = (120 * -1) << 16; this.MouseMove(new Point(x, y)); WindowsAPI.PostMessage(handle, WM_MOUSEWHEEL, (IntPtr)delta, paramHelper.createCoordinatesLParam(xScreenPos, yScreenPos)); }