用datalist显示不了数据 - 编程论坛

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DataList.aspx.cs" Inherits="DataList" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.

<html xmlns="http://www. >
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:DataList ID="DataList1" runat="server">
            <ItemTemplate>
                <asp:Label ID="Label1" runat="server" Text='<%# DataBinder.Eval(Container,"DataItem.RegionDescription")%>'></asp:Label>
            </ItemTemplate>
        </asp:DataList>

    </div>
    </form>
</body>
</html>

后台代码是：
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 DataList : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string connection = "Data Source=.;Initial Catalog=NorthWind;User id=silence;pwd=123456";
        string sql = "select * from Region";
        SqlConnection con = new SqlConnection(connection);
        con.Open();
        SqlDataAdapter da = new SqlDataAdapter(sql, con);
        DataSet ds = new DataSet();
        da.Fill(ds);
        this.DataList1.DataSource = ds;
        this.DataList1.DataBind();
    }
}

运行的时候总是说
编译器错误信息: CS1502: 与“System.(System.Data.DataTable)”最匹配的重载方法具有一些无效参数

源错误:

行 21:         SqlDataAdapter da = new SqlDataAdapter(sql, con);
行 22:         DataSet ds = new DataSet();
行 23:         da.Fill(ds);
行 24:         this.DataList1.DataSource = ds;
行 25:         this.DataList1.DataBind();