Export ASP.Net Panel with GridView DropDownList to PDF using iTextSharp

Hi Mudassar, I have a question for you on the subject to export the contents of a panel to pdf, can export the panel even if it has some controls such as GridView, DropDownList, etc.? I have the following code:    

protected void btnExport_Click (object sender, EventArgs e)
     {
         Response.ContentType = "application / pdf";
         Response.AddHeader ("content-disposition", "attachment; Panel.pdf filename =");
         HtmlForm HtmlForm form_nuevo = new ();
         form_nuevo.Attributes.Add ("runat", "Server");
         form_nuevo.Controls.Add (GridView1);
         Response.Cache.SetCacheability (HttpCacheability.NoCache);
         StringWriter sw = new StringWriter ();
         HtmlTextWriter hw = new HtmlTextWriter (sw);
         pnlPerson.RenderControl (hw);
         StringReader sr = new StringReader (sw.ToString ());
         Document pdfDoc = new Document (PageSize.A4, 10f, 10f, 100f, 0f);
         HTMLWorker HTMLParser = new HTMLWorker (pdfDoc);
         PdfWriter.GetInstance (pdfDoc, Response.OutputStream);
         pdfDoc.Open ();
         htmlparser.Parse (sr);
         pdfDoc.Close ();
         Response.Write (pdfDoc);
         Response.End ();

     }

I had to integrate the GridView to a form that is created at runtime because I said I should be in one, but even so when I export the file I get blank, really I do not know what I'm doing wrong and I have many controls that I have to export thanks for your help