Convert html to pdf

Hi,

I am facing issue while converting a html document into pdf using itextsharp dll in sharepoint visual webpart.I have attached my code below.Can anyone please help me to resolve?

protected void btnsub_Click(object sender, EventArgs e)
        {
            string currentURL = HttpContext.Current.Request.Url.ToString();
            MemoryStream stream = new MemoryStream();
            HttpContext.Current.Response.ContentType = "application/pdf";
            HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename=Panel.pdf");
           // HttpContext.Current.Response.Charset = "";
            // String htmlText = strSelectUserListBuilder.ToString();

            HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
            StringWriter txtWriter = new StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(txtWriter);
            //this.Page.RenderControl(hw);

            div123.RenderControl(hw);//*error

            StringReader sr = new StringReader(txtWriter.ToString());
            iTextSharp.text.Document pdfDoc = new iTextSharp.text.Document(iTextSharp.text.PageSize.A4, 20f, 10f, 10f, 0f);
            HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
            PdfWriter.GetInstance(pdfDoc, stream);

            pdfDoc.Open();
            htmlparser.Parse(sr);
            pdfDoc.Close();
            var bytes = stream.ToArray();
            HttpContext.Current.Response.OutputStream.Write(bytes, 0, bytes.Length);
            HttpContext.Current.Response.OutputStream.Flush();

            HttpContext.Current.Response.Write(pdfDoc);
            HttpContext.Current.Response.End();
        }

This is the code which am trying to get pdf.but am getting an error in (*error)
I tried to resolve it by adding
Enableeventvalidation =true;in page directory
But there is no page directory in ascx page.
After this we need to add
  public override void VerifyRenderingInServerForm(Control control)
        {
            /* Verifies that the control is rendered */
        }
Showing an error like no suitable  method found to override

Poovi