How to sort template field by clickin gridview column header

hey this is my column in my gridview ..i need to use sorting.
condition 1) i dont want to write sql query in codebehind.
i can write in storedprocedure and call in codebehind

then i need to know whether v can sort without any query....
since i dint use boundfield feelin lot of confusion in sorting.
so plz help me

<asp:TemplateField HeaderText="Employeename" SortExpression="Employeename" >
<HeaderTemplate>
<asp:LinkButton ID="lnkgroup" runat="server" CommandArgument="Employeename" CommandName="Sort"
ForeColor="white" Text="<%$ Resources:DefaultResource, Employeename %>"
></asp:LinkButton>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="lab2" runat="server"
Text='<%# Eval("Employeename") %>' Width="300px"></asp:Label>
</ItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TxtId" runat="server"
Width="300px"></asp:TextBox>
</FooterTemplate>
</asp:TemplateField>