protected void Export_Button_Click1(object sender, EventArgs e)
{
Response.Clear();
Response.Buffer = true;
Response.ContentType = "application/vnd.ms-excel";
// Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment;filename=BackupFile.xls");
Response.Charset = "";
this.EnableViewState = false;
System.IO.StringWriter sw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);
R1.RenderControl(htw);
Response.Write(sw.ToString());
Response.End();
}