Show ASP.Net GridView current selected row data when clicked in AJAX ModalPopupExtender

hello,

I am using Ajax toolkit first time 

I dont know how to use it 

in girdview I am using Ajax : ModalPopupExtender 

if I click on studnetid then Student info pop up page should come

Can you please help me ? 

  <asp:TemplateField  HeaderText ="StudentID" SortExpression="StudentID"   >

                   <ItemTemplate  >

                        <asp:LinkButton ID="StudentIDlinkButton" runat="server" Text='<%#Eval("StudentID") %>'   OnClick="ShowPopupwindowforStudentID" />

                      <asp:Panel ID="PanelforStudentDetails" runat="server" Width="200px" Height="200px" Style="display: none;" Direction="LeftToRight">

Student Id 

<br />

<asp:Button ID="btnDummy" text = "OK" runat="server"  />

</asp:Panel><br />

       <asp:ModalPopupExtender ID="PopupwindowforStudent" runat="server" TargetControlID="StudentIDlinkButton"  PopupControlID="PanelforStudentDetails" OkControlID="btnDummy">

    </asp:ModalPopupExtender>

                   </ItemTemplate>                    

                </asp:TemplateField>