后台代码
Code
 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
          
            int nItem = Convert.ToInt32(ListBox1.Items.Count * 20);
            ListBox1.Height = nItem; //Set height depends on the font size.
            ListBox1.Width = 300; //This will ensure the list item won't be shrinked!
        }

    }
前台代码

Code