private void Fetchdata()
        {
            dlInvoiceData = new DLInvoiceData();
            var invoiceDataset = dlInvoiceData.FetchInvoiceRecords(13);
            if (invoiceDataset.Tables.Count > 0)
            {
                var str = ReadInvoiceContent(invoiceDataset);
                if (!string.IsNullOrEmpty(str))
                {
                    Document document = null;
                    document = new Document();
                    string FileName = DateTime.Now.ToString("ddmmyyyyhhmmss");

                    string path = Server.MapPath("~") + "/Invoice/" + FileName + ".pdf";
                    PdfWriter.GetInstance(document, new FileStream(path, FileMode.Create));
                    document.Open();

                    iTextSharp.text.html.simpleparser.HTMLWorker hw =
                            new iTextSharp.text.html.simpleparser.HTMLWorker(document);


                    hw.Parse(new StringReader(str));
                    document.Close();
                    document.Dispose();

                    Response.ContentType = "Application/pdf";
                    Response.AppendHeader("Content-Disposition", "attachment; filename=Voucher.pdf");
                    Response.TransmitFile(path);
                    //Response.OutputStream();
                    Response.End();
                }
            }
        }

private string ReadInvoiceContent(DataSet dataset)
        {
            try
            {
                var _content = string.Empty;
                using (StreamReader reader = new StreamReader(Server.MapPath("~/Invoice/invoice.html")))
                {
                    _content = reader.ReadToEnd();
                }
                if (_content != null)
                {
                    _content = _content.Replace("{Demo}", dataset.Tables[0].Rows[0]["name"].ToString());

                    return _content;
                }
                else
                    return null;
            }
            finally
            {

            }
        }