多级菜单,多级下拉列表解决方案(收藏) 西安

public string listStr = "";
       protected void Page_Load(object sender, EventArgs e)
       {
           LoadList();
       }

       /// <summary>
       /// 加载整个分类表
       /// </summary>
       private void LoadList()
       {
           listStr = "";

           int MTcount = 0;//执行遍历的次数
           //开始迭代加载
           MakeTr("0", MTcount);

       }
       /// <summary>
       /// 装配每一行
       /// </summary>
       /// <param name="id">上级ID</param>
       /// <param name="count">迭代次数</param>
       private void MakeTr(string id, int count)
       {

           DataView dv = Web.App_Code.Live.Live_Class_Manage.GetClassListByParentID(id);
           foreach (DataRowView drv in dv)
           {
               //形成表格
               //listStr += "<tr><td>" + MakeFelgefu(count) + drv["context"].ToString() + "</td><td>自身编号" + drv["id"].ToString() + ",上级编号" + id + "</td></tr>";
               listStr += "<tr><td class=\"td_bg_center\" width=\"20%\" height=\"23\"> " + drv["ClassID"].ToString() + "</td><td class=\"td_bg\" width=\"20%\">" + MakeFelgefu(count) + drv["ClassName"].ToString() + "</td><td class=\"td_bg_center\" width=\"20%\">" + GetParentClassNameByClassID(drv["ClassParentID"].ToString()) + "</td><td class=\"td_bg_center\" width=\"20%\">" + drv["ClassPath"].ToString() + "</td><td class=\"td_bg_center\" width=\"20%\"><a href=\"Live_Class_Add.aspx?ClassID=" + drv["ClassID"].ToString() + "&ParentID=" + drv["ClassParentID"].ToString() + "&Action=Delete\">删除</a> &nbsp;<a href=\"Live_Class_Add.aspx?ClassID=" + drv["ClassID"].ToString() + "&ParentID=" + drv["ClassParentID"].ToString() + "&Action=Update\">修改</a> &nbsp;<a href=\"Live_Class_Add.aspx?ClassID=" + drv["ClassID"].ToString() + "&ParentID=" + drv["ClassParentID"].ToString() + "&Action=Add\">添加子栏目</a></td></tr>";
               //形成下拉列表

               //再次遍历
               MakeTr(drv["ClassID"].ToString(), count + 1);

           }
           dv.Dispose();
       }
       /// <summary>
       /// Make分隔符
       /// </summary>
       /// <param name="count"></param>
       /// <returns></returns>
       private string MakeFelgefu(int count)
       {
           string Returnwords = string.Empty;
           if (count == 0)
           {
               Returnwords = "";
           }

           else
           {
               Returnwords = ("├").PadLeft(count, ' ');
           }
           return Returnwords;
       }

----------------------------------------------------

/// <summary>
        /// 加载整个分类表
        /// </summary>
        private void LoadList()
        {
            ListItem lit = new ListItem("所有栏目", "0");
            ddlClass.Items.Insert(0, lit);

            int MTcount = 0;//执行遍历的次数
            MakeTr("0", MTcount);//开始迭代加载
        }

        /// <summary>
        /// 装配每一行
        /// </summary>
        /// <param name="id">上级ID</param>
        /// <param name="count">迭代次数</param>
        private void MakeTr(string id, int count)
        {
            DataView dv = Web.App_Code.Live.Live_Class_Manage.GetClassListByParentID(id);
            foreach (DataRowView drv in dv)
            {
                //形成下拉列表
                ListItem li = new ListItem(MakeFelgefu(count) + drv["ClassName"].ToString(), drv["ClassID"].ToString());

                ddlClass.Items.Add(li);

                //再次遍历
                MakeTr(drv["ClassID"].ToString(), count + 1);
            }
            dv.Dispose();
        }
        /// <summary>
        /// Make分隔符
        /// </summary>
        /// <param name="count"></param>
        /// <returns></returns>
        private string MakeFelgefu(int count)
        {
            string Returnwords = string.Empty;
            if (count == 0)
            {
                Returnwords = "";
            }

            else
            {
                Returnwords = ("├").PadLeft(count, ' ');
            }
            return Returnwords;
        }