Creating a pdf document

string src = string.Empty;
            string AbsolutePath = string.Empty;
            _Filter.Clear();
            _Filter.Add("Id",hdnCertificateId.Value);
            _CertificatesEntityCollection = CertificatesManager.SelectFiltered(_Filter);

            ScriptManager.RegisterStartupScript(this, typeof(string), "script123", "AsPdf()", true);
            Response.Clear();
            Response.ClearContent();
            Response.ClearHeaders();
            Response.ContentType = "application/pdf";
            //Response.AddHeader("content-disposition", "attachment;filename=" + _CertificatesEntityCollection.First().Name + ".pdf");
            Response.AddHeader("Content-Disposition", "attachment; filename=\"" + _CertificatesEntityCollection.First().Name + "\"");

         

            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            StringWriter sw = new StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(sw);

            pnlCertificate.RenderControl(hw);
            pnlCertificate.Style.Add("border", "2px solid black");
            pnlCertificate.Style.Add("margin-top", "60px");
            pnlCertificate.Style.Add("text-align", "justify");
            
            src = sw.ToString();
            AbsolutePath = HttpContext.Current.Request.Url.Scheme + "://" + HttpContext.Current.Request.Url.Authority + HttpContext.Current.Request.ApplicationPath;
            src = src.Replace("img src=\"/", string.Format("img src=\"{0}", AbsolutePath));
            StringReader sr = new StringReader(src);
            //Document pdfDoc = new Document(PageSize.A4_LANDSCAPE, 20f, 10f, 50f, 0f);
            Document pdfDoc = new Document();
            pdfDoc.SetPageSize(iTextSharp.text.PageSize.A4.Rotate());
            
            HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
            PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
            pdfDoc.Open();
            htmlparser.Parse(sr);
            pdfDoc.Close();
            Response.Write(pdfDoc);
            Response.End();