How to set gridview template field as target control for modal popup extender?

[Aksha]

Is there a way to set control (in template field of gridview) as target control for modal popup extender? I tried like here:Full postback triggered by LinkButton inside GridView inside UpdatePanelBut I get an exception as value parameter can't be null. Please help in detail.Grid:\[code\]<asp:GridView ID="grdTemp" runat="server" AllowPaging="True" AllowSorting="True" DataSourceID="SqlDataSource1" AutoGenerateColumns="False" DataKeyNames="TempNo" OnRowCommand="grdDULead_RowCommand" OnRowDataBound="grdDULead_RowDataBound"> <FooterStyle BackColor="White" CssClass="GridFooter" /> <Columns> <asp:TemplateField><ItemTemplate><asp:LinkButton ID="grDULeadlnkSelect" runat="server" ForeColor="Red" OnClick="grDULeadlnkSelect_Click" CausesValidation="False" CommandName="selectrow">select</asp:LinkButton></ItemTemplate></asp:GridView>\[/code\]Extender:\[code\]<cc1:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="grDULeadlnkSelect" PopupControlID="pnlCDAMTClar" BackgroundCssClass="modalBackground"></cc1:ModalPopupExtender>\[/code\]Code-behind:At the start I got the error \[code\]could not find control "grDULeadlnkSelect"\[/code\]. Then I tried to register button like so but I get the error \[code\]value cannot be null\[/code\].\[code\]protected void grdTemp_RowDataBound(object sender, GridViewRowEventArgs e){ // getting err at below line. LinkButton lb = e.Row.FindControl("grDULeadlnkSelect") as LinkButton; ScriptManager.GetCurrent(this).RegisterAsyncPostBackControl(lb); }\[/code\]