asp.net gridview 问题

asp:TemplateField

/asp:TemplateField








/asp:GridView

报错如下
DataBinding:“System.Data.DataRowView”不包含名为“BookID”的属性。]????
这是后台代码
public partial class BookSearch : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
try
{
//验证Session对象，判断用户是否登陆
if (Session["UserID"].ToString() == "" || Session["UserID"].ToString() == null || Session["Level"].ToString() != "2")
{
Response.Redirect("Login.aspx");
return;
}
}
//Session对象未初始化，跳转登陆页面。
catch (NullReferenceException)
{
Response.Redirect("Login.aspx");
}
lblUserName.Text = Session["UserName"].ToString();
if (!IsPostBack)
{
GridView1.DataSource = BookManager.SelectAllBooks();
GridView1.DataBind();
}
}
protected void btnSearch_Click(object sender, EventArgs e)
{
if (txtkey.Text.Trim() == "")
{
GridView1.DataSource = BookManager.SelectAllBooks();
GridView1.DataBind();
}
else
{
GridView1.DataSource = BookManager.SelectBookByType(DropDownList1.SelectedValue, txtkey.Text);
GridView1.DataBind();
}
}
}