var excelXml = GetExcelXml(dsInput, filename);
        response.Clear();
        response.AppendHeader("Content-Type", "application/vnd.ms-excel");
        response.AppendHeader("Content-disposition", "attachment; filename=" + filename);
        response.Write(excelXml);
        response.Flush();

protected void btnExport_Click(object sender, EventArgs e)
{
    try
    {

        if (list.Count() > 0)
        {


            ds.Tables.Add(dtForExport);
            ExcelHelper.ToExcel(ds, filename); //To Excel method is described above.
            LoadGridDetails();//Binds the new values

        }

    }
    catch (Exception ex)
    {
        lblStatus.Text = "Error Exporting to Excel";
    }
}//Screen is not refreshed after executing this line.