问从SQLServer绑定到GridView的信息在C#中不起作用

EN

  <asp:GridView ID="gvUploadDocumentList" runat="server" AutoGenerateColumns="False" 
                   BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" 
                   BorderWidth="1px" CellPadding="4" EmptyDataText="No files uploaded" 
                   ForeColor="Black" GridLines="Horizontal" style="text-align: center;
                   margin:0px auto;" Width="800px">
          <Columns>
                <asp:BoundField DataField="Filename" HeaderText="File Name" />  
                <asp:TemplateField>
                      <ItemTemplate>
                              <asp:LinkButton ID="lnkDelete" runat="server" CommandArgument='<%# Eval("ID") %>' Text="Delete" OnClick="DeleteFile" />
                      </ItemTemplate>
                </asp:TemplateField>
          </Columns>
                <FooterStyle BackColor="#CCCC99" ForeColor="Black" />
                <HeaderStyle BackColor="#333333" Font-Bold="True" ForeColor="White" />
                <PagerStyle BackColor="White" ForeColor="Black" HorizontalAlign="Right" />
                <SelectedRowStyle BackColor="#CC3333" Font-Bold="True" ForeColor="White" />
                <SortedAscendingCellStyle BackColor="#F7F7F7" />
                <SortedAscendingHeaderStyle BackColor="#4B4B4B" />
                <SortedDescendingCellStyle BackColor="#E5E5E5" />
                <SortedDescendingHeaderStyle BackColor="#242121" />
  </asp:GridView>

    protected void Page_Load(object sender, EventArgs e)
    {
         if(!page.IsPostBack)
         {
             LoadRequestInfo();
             LoadDocuments();
         }
    }

    public void LoadDocuments()
    {
        CommonCollection c = new CommonCollection();
        var CTS = c.COMPTRACKERCONNECTIONSTRING();
        var CTS_conn = new SqlConnection(CTS.ConnectionString);
        try
        {
            SqlCommand cmd = new SqlCommand("CTS_GetDocuments", CTS_conn);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add(new SqlParameter("@RequestId", "1F0C0732-34CD-48DC-9730-268FE17BAF03"));
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            CTS_conn.Open();
            da.Fill(ds);
            CTS_conn.Close();

            if (ds != null && ds.Tables[0].Rows.Count > 0)
            {
                gvUploadDocumentList.DataSource = ds;
                gvUploadDocumentList.DataBind();
                ShowAlertMessage("Table is not empty");
            }
            else
                ShowAlertMessage("No Data");
         }
         catch (Exception ex)
         {
              ShowAlertMessage(ex.Message.ToString());
         }
    }