C# treeview绑定

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                bindTree();
            }
        }
        private void bindTree()
        {
            ALIYUN_PIC.BLL.Folder_oper_BLL bll = new Folder_oper_BLL();
            
            DataTable dt = bll.PIC_Bind();//得到需要的datatable
            this.FillNode(dt, null);
        }
        private void FillNode(DataTable dt, TreeNode node)
        {
            DataView dv = new DataView(dt);
            if (node == null)    //根结点
            {
                dv.RowFilter = "PARENT_NODE='0'";  //筛选到根结点的所有子节点
            }
            else  //不是根结点
            {
                dv.RowFilter = "PARENT_NODE='" + node.Value + "'";   //筛选对应节点的所有子节点
            }
            foreach (DataRowView drv in dv)   //遍历填充节点的所有子节点，如果传入的节点node为叶子节点，遍历要退出，不再进行递归
            {
                TreeNode no = new TreeNode(drv["NODE_NAME"].ToString(), drv["id"].ToString());
                FillNode(dt, no);  //填充no节点的子节点
                if (node == null)
                {                  
                    this.PIC_TREE.Nodes.Add(no);
                }
                else
                {
                    node.ChildNodes.Add(no);
                }
            }
        }