panel 绑定鼠标滚轮事件

void formsample_mousewheel(object sender, MouseEventArgs e)
        {
            //获取光标位置
            Point mousepoint = new Point(e.X, e.Y);
            //换算成相对本窗体的位置
            mousepoint.Offset(this.Location.X, this.Location.Y);
            //判断是否在panel内
            if (pl_message.RectangleToScreen(pl_message.DisplayRectangle).Contains(mousepoint))
            {
                //滚动
                pl_message.AutoScrollPosition = new Point(0, pl_message.VerticalScroll.Value - e.Delta);
            }
        }

 this.MouseWheel += formsample_mousewheel;