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";
}

}
}