private void FormSample_Load(object sender, EventArgs e)
        {

            //注册事件
            this.MouseWheel += new MouseEventHandler(FormSample_MouseWheel);
        }

        ///
        /// 滚动方法
        ///
        ///
        ///
        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 (pnlDownload.RectangleToScreen(
              pnlDownload.DisplayRectangle).Contains(mousePoint))
            {
                //滚动
                pnlDownload.AutoScrollPosition = new Point(
, pnlDownload.VerticalScroll.Value - e.Delta);
            }
        }