Unable to Import Grid data on pdf

Question

Hi everyone

I am importing data from grid view to pdf but when I am trying to open that pdf file it is showing some error like "there was an error opening this document the file is damaged and could not be repaired pdf"

But I am able to open some other pdf files.
i have written code like this. can you any one tell me how to overcome this issue its very urgent.

CODE:

Response.ContentType = "application/pdf";
Response.AddHeader("content-disposition",
"attachment;filename=GridViewExport.pdf");
Response.Cache.SetCacheability(HttpCacheability.NoCache);
StringWriter sw = new StringWriter();
HtmlTextWriter hw = new HtmlTextWriter(sw);
Gridview1.AllowPaging = false;
Gridview1.DataBind();
Gridview1.RenderControl(hw);
StringReader sr = new StringReader(sw.ToString());
Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
pdfDoc.Open();
htmlparser.Parse(sr);
//pdfDoc.Close();
System.Web.HttpContext.Current.Response.Write(pdfDoc);
//Response.Write(pdfDoc);
Response.End(); 

Thanks in Advance
Satish Madugundu