Dynamically create and display ASP.Net AJAX ModalPopupExtender modal popup

Hi All

I hav One dynamically created LinkButton in Table.. I want dispaly Modal popup exrender Link button Click event.. on

What Should i specify In TargetControlId field=?..

i tried

void amendQty_Click(object sender, EventArgs e)

{ //throw new NotImplementedException();

LinkButton amendQty = sender as LinkButton;

amendQty.ID = "lnkamend";

popupwin.TargetControlId="lnkamend";

this.popupwin.show()

}

but itd doesnt work.. and also i tried

 void amendQty_Click(object sender, EventArgs e)
    {
        //throw new NotImplementedException();
        LinkButton amendQty = sender as LinkButton;
        amendQty.ID = "lnlamend";
        AjaxControlToolkit.ModalPopupExtender modalPop = new AjaxControlToolkit.ModalPopupExtender();
        modalPop.ID = "ModalPopupExtenderSelectFilds";
        modalPop.PopupControlID = Convert.ToString(Page.FindControl(Convert.ToString(pnppopup))); //panel.ID;
        modalPop.TargetControlID = Convert.ToString(Page.FindControl(Convert.ToString("lnlamend"))); //"hdnField";        
    
        modalPop.BackgroundCssClass = "modalPopup";
      
        modalPop.CancelControlID = "btnClose";
        modalPop.Show();
}

its showing nothing