Reg: Input string was in correct format

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C#

ASP.NET

Hai here i am converting a total div to pdf format.\

This is my code

Response.ContentType = "application/pdf";
       Response.AddHeader("content-disposition", "attachment;filename=UserDetails.pdf");
       Response.Cache.SetCacheability(HttpCacheability.NoCache);
       StringWriter sw = new StringWriter();
       HtmlTextWriter hw = new HtmlTextWriter(sw);
       this.InvoiceBody.RenderControl(hw);
       StringReader sr = new StringReader(sw.ToString());
       Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 100f, 0.0f);
       HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
       PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
       pdfDoc.Open();
       htmlparser.Parse(sr);
       pdfDoc.Close();
       Response.Write(pdfDoc);
       Response.End();

Here i am getting the error Input string was incorrect format.

Please help me