multiple select buttons in gridview

Hi friends,

I have a gridview with to link buttons in the tempalte field as shown below.. I need to open two diffrent panels when  each button is clicked one panel for Edita nd one for Add.. But how can i determine which button has been clciked in the gvCustomers_SelectedIndexChanged event.. I am confused as it does not allow the  e.CommandName property here..  Thank you
 <asp:TemplateField>  
                        <ItemTemplate>
                        <asp:LinkButton ID="btnViewDetails"  runat="server" Text="Edit"  CommandName="Select" />
                      ...