Query string and Eval in gridview

Hi guys
I would like to know how i can create a query string for on of my Eval in my gridview to get the info of this row and use it in another part in the page, in the below code i want to add query string to the label to get the full info later depending of mailno

<asp:TemplateField> <ItemTemplate> <asp:Label ID="Label10" runat="server" Style="color: #FFFFFF" Text='<%# Bind ("mailno") %>'></asp:Label> </ItemTemplate> </asp:TemplateField>