简单的递归

   #region 递归绑定树
        /// <summary>
        /// 操作数据库取值
        /// </summary>
        /// <returns></returns>
        private DataTable InitDataTable()
        {
            BLL.JC_Form.JC_CommZoneBasicInfo cb = new BLL.JC_Form.JC_CommZoneBasicInfo();
            dt = cb.GetJC_CommZoneBasicInfoList("").Tables[0];
            return dt;
        }
        /// <summary>
        /// 绑定树
        /// </summary>
        private void BindRoot()
        {
            //调用查询方法
            InitDataTable();
            //把父节点的数据帅选出来
            DataRow[] rows = dt.Select("ParentsID=0");//取根  
            //循环遍历
            foreach (DataRow dRow in rows)
            {
                TreeNode rootNode = new TreeNode();
                rootNode.Tag = dRow["ZoneID"].ToString();
                //把数据里父节点的名字复制给节点
                rootNode.Text = dRow["ZoneName"].ToString();
                //把此节点放入树中
                tv.Nodes.Add(rootNode);
                //绑定子节点
                BindChildAreas(rootNode);
            }
        }
        /// <summary>
        /// 绑定子节点
        /// </summary>
        /// <param name="fNode"></param>
        private void BindChildAreas(TreeNode fNode)
        {
            //DataRow dr = (DataRow)fNode.Tag;           
            //把父节点的id赋值给变量
            int fAreaId = Convert.ToInt32(fNode.Tag);//(int)dr["ZoneID"];
            //找到父节点是变量fAreaId的数据
            DataRow[] rows = dt.Select("ParentsID=" + fAreaId);
            //判断是否为空
            if (rows.Length == 0) { return; }
            //循环遍历
            foreach (DataRow dRow in rows)
            {
                TreeNode node = new TreeNode();
                node.Tag = dRow["ZoneID"].ToString();
                //子节点的名字
                node.Text = dRow["ZoneName"].ToString();
                //把此节点加入子节点中
                fNode.Nodes.Add(node);
                BindChildAreas(node);
            }
        }
        #endregion