Gridview sorting with template field in ASP.Net

boundfield sort is working but template field sort not working

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnSelectedIndexChanged="GridView1_SelectedIndexChanged" Width="371px" PageSize="5" AllowSorting="True" onsorting="GridView1_Sorting" OnRowDeleting="OnRowDeleting">
   <Columns>
        <asp:TemplateField  HeaderText='<img width="20px" height="20px" src="Images/updown.png"/>Id'  ItemStyle-HorizontalAlign="Center" SortExpression="Id" >
           <ItemTemplate>
              <%#Container.DataItemIndex+1%>
           </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="LoanType" HeaderText="LoanType" SortExpression="LoanType" />
        <asp:BoundField DataField="LoanTerm" HeaderText="Term(Years)" SortExpression="LoanTerm" />
        <asp:BoundField DataField="LoanRate" HeaderText="LoanRate" SortExpression="LoanRate" />
        <asp:BoundField DataField="LoanEffectFrom" HeaderText="Loan Effect From" SortExpression="LoanEffectFrom" />
        <asp:BoundField DataField="LoanMaturity" HeaderText="Loan Maturity Date" SortExpression="LoanMaturity" />
        <asp:CommandField HeaderText="Edit" SelectText="Edit" ShowSelectButton="True" />
        <asp:CommandField HeaderText="Delete" ShowDeleteButton="True" ShowHeader="True" />
   </Columns>
</asp:GridView>