打开现有的pdf，并插入一个图片

不说了，直接代码
T_ScanUploadData file = _IScanUploadDataAccessService.GetScanUploadData(id);

            byte[] filedata = FineUploaderUtil.DownloadData(file.SignDocPath);

            string filename = Server.MapPath("//pictemp/") + "downSignDoc.pdf";

            //using (Stream inputPdfStream = new FileStream(@"d:\Users\Administrator\Desktop\xml\111.pdf", FileMode.Open, FileAccess.Read, FileShare.Read))

            //using (Stream inputImageStream = new FileStream(@"d:\Users\Administrator\Desktop\xml\myimage.jpg", FileMode.Open, FileAccess.Read, FileShare.Read))

            using (Stream outputPdfStream = new FileStream(filename, FileMode.Create, FileAccess.ReadWrite, FileShare.None)) {

                var reader = new PdfReader(filedata);

                var stamper = new PdfStamper(reader, outputPdfStream);

                var pdfContentByte = stamper.GetOverContent();

                iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(BarCodeHelper.MakeBarcodeImage(barcode, , true), BaseColor.WHITE);

                image.SetAbsolutePosition(, );

                pdfContentByte.AddImage(image);

                stamper.Close();

                Stream outputStream = new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.None);

                int length = (int)outputStream.Length;

                byte[] data = new byte[length];

                outputStream.Position = ;

                outputStream.Read(data, , length);

                MemoryStream ms = new MemoryStream(data);

                Response.AppendHeader("Content-Disposition", "attachment;filename=" + "" + file.OrderNo + "." + System.IO.Path.GetExtension(file.SignDocPath));

                Response.BinaryWrite(ms.ToArray());

                Response.End();

                ms.Close();

                ms = null;

            }
用的iTextSharp。