How to export data in excel sheet?

try
{
           string attachment = "attachment; filename=Export.xls";
           Response.ClearContent();
           Response.AddHeader("content-disposition", attachment);
           Response.ContentType = "application/ms-excel";
           StringWriter sw = new StringWriter();
           HtmlTextWriter htw = new HtmlTextWriter(sw);
           HtmlForm frm = new HtmlForm();
           GRD_Final_Report.Parent.Controls.Add(frm);
           frm.Attributes["runat"] = "server";
           frm.Controls.Add(GRD_Final_Report);
           frm.RenderControl(htw);
           Response.Write(sw.ToString());
           Response.End();
}
Catch(Exception ex)
{
}