public void ExportDataGridToExcel(System.Web.UI.Control ctrl, System.Web.HttpResponse response)
{
response.Clear();
response.Buffer = true;
response.Cache.SetCacheability(HttpCacheability.NoCache);
response.ContentType = "application/vnd.ms-excel";
response.AddHeader("content-disposition", "attachment;filename=Flash Report.xls");
response.Charset = "";
this.EnableViewState = false;
System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
//this.ClearControls(ctrl);
ctrl.RenderControl(oHtmlTextWriter);
// set content type and character set to cope with european chars like the umlaut.
response.Write("<meta http-equiv=Content-Type content=\"text/html; charset=utf-8\">" + Environment.NewLine);
// add the style props to get the page orientation
response.Write(AddExcelStyling());
response.Write("<span style='font-size: 11pt; font-family: Arial; font-weight:bold;'>" + "REPORTE EXCESO DE INVENTARIO" + indicadorTexto + "</span>");
response.Write("<br>");
response.Write("<span style='font-size: 10pt; font-family: Arial;'>" + lblLeyenda.Text + "</span>");
response.Write("<br>");
response.Write("<br>");
response.Write(oStringWriter.ToString());
response.Write("</body>");
response.Write("</html>");
response.End();
}