menu遇到问题,在线等,请各位帮帮忙


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.OleDb;public partial class menutest : System.Web.UI.Page
{
    OleDbConnection cn;
    OleDbDataAdapter pda;
    DataSet pds;
    OleDbDataAdapter cda;
    DataSet cds;
    OleDbCommand cmd;
    OleDbDataReader dr;
    int i, xlnum;    protected void Page_Load(object sender, EventArgs e)
    {
        cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("App_Data\\infomation.mdb") + ";");
        if (!Page.IsPostBack)
        {            
            cn.Open();
            Response.Write("sdf");//这里当我加了这句,预览的时候,鼠标指向一级的时候二级会显示,
            //但是一旦点击就又不显示二级了,如果把这一句删除掉,运行就只显示一级,请问是什么原因            pda = new OleDbDataAdapter("SELECT * FROM dl ORDER BY dl_taxis ASC", cn);
            pds = new DataSet();
            pda.Fill(pds);
            for (i = 0; i < pds.Tables[0].Rows.Count; i++)
            {
                MenuItem pmi = new MenuItem(pds.Tables[0].Rows[i]["dl_name"].ToString());
                Menu1.Items.Add(pmi);
                cda = new OleDbDataAdapter("SELECT * FROM xl WHERE (xl_dlid=" + pds.Tables[0].Rows[i]["dl_id"] + ") ORDER BY xl_taxis ASC", cn);
                cds = new DataSet();
                cda.Fill(cds);
                for (xlnum = 0; xlnum < cds.Tables[0].Rows.Count; xlnum++)
                {
                    MenuItem cmi = new MenuItem(cds.Tables[0].Rows[xlnum]["xl_name"].ToString());
                    pmi.ChildItems.Add(cmi);
                }
                cn.Close();
            }
        }
    }
}