asp.net treeview绑定数据库，并取节点和节点的内容

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using AlltripDLL;

public partial class visa_tree : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            bindtree(0);
        }

      

    }
    public void bindtree(int id)
    {
        treeclass tree = new treeclass();
        DataTable ds = tree.selectnode(id);
        for (int i = 0; i < ds.Rows.Count; i++)
        {
            TreeNode node = new TreeNode();
            node.PopulateOnDemand =false;
            node.Text = ds.Rows[i]["nodesname"].ToString();
            node.Value = ds.Rows[i]["nodesid"].ToString();
            TreeView1.Nodes.Add(node);
            //node.NavigateUrl = "list.aspx";
            node.SelectAction = TreeNodeSelectAction.Expand;
            bingChildnodes(node);
        }
    }
    public void bingChildnodes(TreeNode rootnode)
    {
        treeclass tree = new treeclass();
        DataTable dt =tree.selectnode(int.Parse(rootnode.Value));
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            TreeNode node = new TreeNode();
            node.Text = dt.Rows[i]["nodesname"].ToString();
            node.Value = dt.Rows[i]["nodesid"].ToString();
            rootnode.ChildNodes.Add(node);
          //  node.NavigateUrl = "index.aspx";
            bingChildnodes(node);
        }

   
    }

    protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
    {
        string strnode = TreeView1.SelectedNode.Value;
        treeclass tree = new treeclass();
        DataTable dt = tree.selectnodechild(int.Parse(strnode));
        if (dt.Rows.Count > 0)
        {
            TextBox1.Text = dt.Rows[0]["nodes"].ToString();
        }
        else
        {
            TextBox1.Text = "无数据";
        }
      
    

    }
}