System.Web.UI.Page”并不包含“DataItem”的定义

aspx:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="edit_admin_datum.aspx.cs" Inherits="admin_admin_edit_admin_datum" %>
<%@ Import Namespace="System.Data"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>管理员资料修改－YY3721</title>
     <link href="../style/sys_edit_admin.css" rel="stylesheet" type="text/css"/>
</head>
<body bgcolor="#9CC7EF">
    <form id="form1" runat="server" action="edit_admin_datum.aspx">
            
   
        <table width="70%" border="1" align="center" cellpadding="0" cellspacing="0">
  <tr align="center"> 
    <td  height="40" colspan="2"> <span class="add_manage_title"> 修改管理员 <span class="edit_admin_title"> 
  
  <%# DataBinder.Eval(Container.DataItem, "Admin_name")%>
  
  
    </span> 资料</span></td>
  </tr>
  <tr align="center">
    <td  height="30" style="width: 441px" align="right">帐号：</td>
    <td width="474"  height="30" colspan="-1" align="left">
        <input id="Text1" type="text" value=" <%# DataBinder.Eval(Container.DataItem, "Admin_name")%>" />&nbsp;</td>
  </tr>
  <tr align="center">
    <td  height="30" style="width: 441px" align="right">
        密码：</td>
    <td  height="30" colspan="-1" align="left">
        <input id="Text2" type="text" value=" <%# DataBinder.Eval(Container.DataItem, "Admin_name")%>" />&nbsp;</td>
  </tr>
  <tr align="center">
    <td  height="30" style="width: 441px" align="right">权限：</td>
    <td  height="30" colspan="-1" align="left">
        <asp:Label ID="lbl_level" runat="server" Text="Label"></asp:Label>&nbsp;</td>
  </tr>
  <tr align="center">
    <td colspan="2" style="height: 30px" align="center">
        <asp:Button ID="Button1" runat="server" Text="提 交" OnClick="Button1_Click" />
        <input id="Button2" type="button" value="取 消" /></td>
  </tr>             </table>    </form>
</body>
</html>
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;public partial class admin_admin_edit_admin_datum : System.Web.UI.Page
{
    protected int admin_id;
    protected string str_sql;
    protected SqlConnection con_id;
    protected SqlDataReader sdr_id;
    protected SqlCommand cmd_id;
   //protected DataSet ds_id;
    protected void Page_Load(object sender, EventArgs e)
    {
      
       
        admin_id = Convert.ToInt32(Request.QueryString["Admin_id"]);
        admin_id = 1;
        if (isNumeric(admin_id.ToString()))
        {
            str_sql = "select Admin_id,Admin_name,Admin_pwd,Admin_level from admin where admin_id = '" + admin_id + "'";
            con_id = new SqlConnection(ConfigurationSettings.AppSettings["Str_sql"]);
            con_id.Open();
            cmd_id = new SqlCommand(str_sql, con_id);
            sdr_id = cmd_id.ExecuteReader();
         //   lbl_level.Text = sdr_id.GetInt32(3).ToString();
            Page.DataBind();
            con_id.Close();        }
        else
        {
            Response.Write("<script>alert('无效参数');</script>");        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {    }
    private bool isNumeric(string str)                         //判断传入的是否数字
    {
        if (str == null || str.Length == 0)
            return false;
        System.Text.ASCIIEncoding ascii = new System.Text.ASCIIEncoding();
        byte[] bytestr = ascii.GetBytes(str);
        foreach (byte c in bytestr)
        {
            if (c < 48 || c > 57)
            {
                return false;
            }
        }
        return true;
    }
}