pdf is getting downloaded but failing to open in asp.net - pdf

Question

I have a piece of code which exports the Datatable to pdf. When I try to download the pdf, it downloads successfully but it get will not open. I am using the iTextSharp library. Here is my code:
var document = new Document(PageSize.A4, 10, 10, 10, 10);
var output = new MemoryStream();
PdfWriter writer= PdfWriter.GetInstance(document, output);
document.Open();
iTextSharp.text.Font font5 = iTextSharp.text.FontFactory.GetFont(FontFactory.HELVETICA, 5);
Paragraph p = new Paragraph();
p.Alignment = Element.ALIGN_CENTER;
document.Add(p);
if (dt != null)
{
//Craete instance of the pdf table and set the number of column in that table
PdfPTable PdfTable = new PdfPTable(dt.Columns.Count);
PdfPCell PdfPCell = null;
for (int rows = 0; rows < dt.Rows.Count; rows++)
{
for (int column = 0; column < dt.Columns.Count; column++)
{
PdfPCell = new PdfPCell(new Phrase(new Chunk(dt.Rows[rows][column].ToString())));
PdfTable.AddCell(PdfPCell);
}
}
document.Add(PdfTable);
document.Close();
}
HttpContext.Current.Response.ContentType = "application/pdf";
HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", reportname + "_Report_" + DateTime.Now.Date.ToString("yyyy_MMM_dd") + ".pdf"));
HttpContext.Current.Response.Write(document);
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
Can anybody please tell me what the problem is?

Answer 1

The OP writes an iTextSharp Document instance to the HTTP response:
var document = new Document(PageSize.A4, 10, 10, 10, 10);
var output = new MemoryStream();
PdfWriter writer= PdfWriter.GetInstance(document, output);
document.Open();
...
HttpContext.Current.Response.Write(document);
This is wrong, that Document instance only is an object to forward material to which is to be arranged and drawn to the PDF. The actual PDF is output to the MemoryStream instance for which the PdfWriter is instantiated. Thus, this stream's content has to be returned.
In reaction to a comment to that effect, the OP fixed the problem using
HttpContext.Current.Response.BinaryWrite(output.ToArray());
instead.