c#datalist连接数据库但是没有显示数据



sno:
<asp:Label ID="au_idlabel" runat="server" Text='<%#Eval("sno") %>'/>


sname:
<asp:Label ID="au_fnamelabel" runat="server" Text='<%#Eval("sname") %>'/>


sex :
<asp:Label ID="lable2" runat="server" Text='<%#Eval("sex") %>'/>


sage:
<asp:Label ID="citylable" runat="server" Text='<%#Eval("sage") %>'/>


sdept:
<asp:Label ID="label3" runat="server" Text='<%#Eval("sdept") %>'/>



public db()
{
connstring = "server = localhost; trusted_connection = SSPI; database = 程序设计";
pagesize = 4;
}
public DataTable dt (string query)
{
SqlConnection con = new SqlConnection(connstring);
SqlDataAdapter sda = new SqlDataAdapter(query, con);
DataSet ds = new DataSet();
sda.Fill(ds, "student");
return ds.Tables["student"];
}

public partial class 修改功能 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack) ;
{
db ndb = new db();
DataList1.DataSource = ndb.dt("select* from student");
DataList1.DataKeyField = "sno";
DataList1.DataBind();
}
}
}

搞课设 急

查出来有数据吗