.net DropDownList 树型显示

 /// <summary>
        /// 构建树形结构的下拉列表
        /// </summary>
        /// <param name="DropDown">传入的dropList控件的名字</param>
        /// <param name="dt">数据源</param>
        /// <param name="DataTextField">显示文本的字段</param>
        /// <param name="DataValueField">显示值的字段</param>
        public static void BindDropDownTree(DropDownList DropDown, DataTable dt, string DataTextField, string DataValueField, string FuID, string fid)
        {
            //DataRow[] row = dt.Select(FuID + "=0");
            DataRow[] row = dt.Select(FuID + "='" + fid + "'");
            //添加根目录
            for (int j = 0; j < row.Length; j++)
            {
                ListItem li = new ListItem(row[j][DataTextField].ToString(), row[j][DataValueField].ToString());
                DropDown.Items.Add(li);
                DropDownListBound("", Convert.ToInt32(row[j][DataValueField]), dt, 1, DropDown, DataTextField, DataValueField, FuID);
            }
        }



        /// <summary>
        /// 递归绑定
        /// </summary>
        /// <param name="Pading">连接字符</param>
        /// <param name="DirId">父节点ID</param>
        /// <param name="dt">传入的数据源</param>
        /// <param name="deep">第几级</param>
        /// <param name="DropDown">传入的dropList控件</param>