gridview中的数据源调试时有数据，但是运行结果却没有数据显示

Question

如题，在设计界面绑定数据源就有数据显示，但是在后台代码绑定就出现问题了，请高手帮忙看看，谢谢
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;public partial class TypedDataSet : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            AuthorsTableAdapters.UserInfoTableAdapter ta = new AuthorsTableAdapters.UserInfoTableAdapter();
            GridView1.DataSource = ta.GetData();
            GridView1.DataBind();
            Response.Write(ta.GetData().Rows[0]["username"].ToString());
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        DataClassesDataContext db = new DataClassesDataContext();
        GridView1.DataSource =from a in db.UserInfo select a;
        GridView1.DataBind();
    }
}

Answer 1

GridView中怎么写的？ 里面有没写类似 <asp:BoundField DataField="id" HeaderText="ID" />这样的代码？ 
  <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="true"> 
        <Columns> 
          <asp:BoundField DataField="id" HeaderText="ID" /> 
        </Columns> 
    </asp:GridView> 或者试下AutoGenerateColumns="true"： <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="true"> 
    </asp:GridView>

Answer 2

GridView1.DataSource =from a in db.UserInfo select a; 
----------------------这个就错了