<asp:ModalPopupExtender ID="modalPopupExtender" runat="server" TargetControlID="btnPupupshow"
BackgroundCssClass="modalBackground" ClientIDMode="Inherit" PopupControlID="pnlDispControl"
DropShadow="true" CancelControlID="btnCancel">
</asp:ModalPopupExtender>
btnPupupshow:Id of the grid viewlinkcolumn
pnlDispControl: A panel containing the new form .