public Form4()
        {
            InitializeComponent();

            foreach (Control gbox in groupBox1.Controls)
            {
                if (gbox is VScrollBar) continue;
                gbox .Tag = panel.Location.Y;
            }

     }

新增一個vScrollBar控制元件，加上此事件

      private void vScrollBar2_Scroll(object sender, ScrollEventArgs e)
        {
            foreach (Control gbox in groupBox1.Controls)
            {
                if (gbox is VScrollBar) continue;
                gbox .Location = new Point(gbox .Location.X, (int)gbox .Tag - e.NewValue);
            }
        }

另外將panel的AutoScroll的屬性設為ture就可以顯示滾動條了了

將滾動條位置置於最低端

 pnlMessage.VerticalScroll.Value = pnlMessage.VerticalScroll.Maximum;