C#与SQL Server 2000实现无限级菜单

//tree.aspx.cs
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 System.Data.SqlClient;
using System.Threading;
 
public partial class MenuTree : System.Web.UI.Page
{
    SqlDataAdapter da = null;
    SqlConnection con = new SqlConnection("server=test;database=DQYPSite_oa;uid=sa;pwd=mfeilgm");
    int i = 0;
    int count = 0;
    int proID = 0;
    int column = 0;
    string nextClassParentID;
    string nextnode;
    ArrayList columD = new ArrayList();
    DataSet TreeTable = new DataSet();
   
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            string cmdStr = "select * from YP_FileClass order by ClassID";
            da = new SqlDataAdapter(cmdStr, con);
            da.Fill(TreeTable,"ClassForlder");
            this.count = TreeTable.Tables["ClassForlder"].Rows.Count;
            if (this.count > 0)
            {
                CreatNode(i);
            }
            els