private void FormSample_Load(object sender, EventArgs e)
        {

            //注冊事件
            this.MouseWheel += new MouseEventHandler(FormSample_MouseWheel);
        }

        /// <summary>
        /// 滾動方法
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void FormSample_MouseWheel(object sender, MouseEventArgs e)
        {
            //獲取光標位置
            Point mousePoint = new Point(e.X,e.Y);
            //換算成相對本窗體的位置
            mousePoint.Offset(this.Location.X, this.Location.Y);      
            //判斷是否在panel內
            if (pnlDownload.RectangleToScreen(
              pnlDownload.DisplayRectangle).Contains(mousePoint))
            {
                //滾動
                pnlDownload.AutoScrollPosition = new Point(
, pnlDownload.VerticalScroll.Value - e.Delta);
            }
        }