C# 如果使用母版存在PDF，请单击“附加”页

我使用以下方法获取两个pdf（CADPDF和TemplatePDF），并将它们叠加为另一个pdf（FinalPDF）

一切都很好，但是现在如果这个FinalPDF已经存在，我需要附加另一个页面。我已经将FileStream的FileMode更改为append，但是FinalPDF被覆盖而不是added

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非常感谢您的指导。

我使用内存流和字节[]数组在iTextSharp中获得了最佳效果。我使用PdfSmartCopy类生成了一个空白PDF，然后从不同的源中检索所需的元素作为字节[]

使用以下方法使用PdfStamper返回数据的字节[]

        public byte[] GetContentToMerge(string CADPDF, string TemplatePDF, string oldData, string newData, string jobNumber, string customer, string designer, string date)
    {

        using (MemoryStream ms = new MemoryStream())
        {

            PdfReader reader = new PdfReader(TemplatePDF);
            PdfReader reader2 = new PdfReader(CADPDF);

            // Use a Memory stream instead of a filestream 
            PdfStamper stamper = new PdfStamper(reader, ms);

            //PSModel psModel = powerSHAPE.ActiveModel;

            try
            {

                AcroFields fields = stamper.AcroFields;

                fields.SetField("oldDataField", oldData);
                fields.SetField("newDataField", newData);
                fields.SetField("jobNumberField", jobNumber);
                fields.SetField("customerField", customer);
                fields.SetField("dateField", date);
                fields.SetField("designerField", designer);
                stamper.FormFlattening = false;

                PdfImportedPage page = stamper.GetImportedPage(reader2, 1);
                PdfContentByte cb;

                cb = stamper.GetOverContent(1);
                cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(1).Height);

                stamper.Close();
                reader.Close();
                reader2.Close();

                // The content you wanted to create is in a memory stream. 
                // It can bee appended to a PDF as a byte[] 
                byte[] ContentToAppend = ms.ToArray();
                return ContentToAppend;

            }
            catch
            {
                System.Windows.MessageBox.Show("Unable to merge drawing with template!");                    
            }

            stamper.Close();
        }

        // If we made it here, something went wrong.
        return new byte[0];
    }

使用该方法，您可以从父方法调用它并以编程方式进行追加

        public void MergePDFs(string CADPDF, string TemplatePDF, string FinalPDF, string oldData, string newData, string jobNumber, string customer, string designer, string date)
    {
            using (Document oDoc = new Document())
            using (MemoryStream ms = new MemoryStream())
            {

                PdfSmartCopy oPDF = new PdfSmartCopy(oDoc, ms);
                oDoc.Open();

                // If the FinalPDF file already exists, load it's data into the PDF 1st.
                if (File.Exists(FinalPDF))
                {
                    byte[] bytesFinalPDF = File.ReadAllBytes(FinalPDF);
                    oPDF.AddDocument(new PdfReader(bytesFinalPDF));
                }
                // If it doesn't exist, the oPDF is blank at this point.

                // Second  add the CAD and Template data to the PDF
                // We do this by calling the GetContentToMerge method which returns the byte array of data that was created using the stamper.
                byte[] ContentToAdd = GetContentToMerge(CADPDF, TemplatePDF, oldData, newData, jobNumber, customer, designer, date);
                if (ContentToAdd.Length > 0)
                {
                    oPDF.AddDocument(new PdfReader(ContentToAdd));
                }

                oDoc.Close();

                // Take whatever went into oPDF object's memory stream and write it to a file with path FinalPDF
                File.WriteAllBytes(FinalPDF, ms.ToArray());
            }
    }

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**我没有100%调试此文件，因此可能需要对检查文件是否存在、读/写权限等进行一些清理。

FileMode.Append

当然是错误的。iText的输出始终是整个结果文件。只要结果位置上的文件长度超过零，就会产生

FileMode.Append

无效PDF中的t（无论Adobe Reader是否识别它，这是另一回事）。这看起来正是我需要的。非常感谢！

        public void MergePDFs(string CADPDF, string TemplatePDF, string FinalPDF, string oldData, string newData, string jobNumber, string customer, string designer, string date)
    {
            using (Document oDoc = new Document())
            using (MemoryStream ms = new MemoryStream())
            {

                PdfSmartCopy oPDF = new PdfSmartCopy(oDoc, ms);
                oDoc.Open();

                // If the FinalPDF file already exists, load it's data into the PDF 1st.
                if (File.Exists(FinalPDF))
                {
                    byte[] bytesFinalPDF = File.ReadAllBytes(FinalPDF);
                    oPDF.AddDocument(new PdfReader(bytesFinalPDF));
                }
                // If it doesn't exist, the oPDF is blank at this point.

                // Second  add the CAD and Template data to the PDF
                // We do this by calling the GetContentToMerge method which returns the byte array of data that was created using the stamper.
                byte[] ContentToAdd = GetContentToMerge(CADPDF, TemplatePDF, oldData, newData, jobNumber, customer, designer, date);
                if (ContentToAdd.Length > 0)
                {
                    oPDF.AddDocument(new PdfReader(ContentToAdd));
                }

                oDoc.Close();

                // Take whatever went into oPDF object's memory stream and write it to a file with path FinalPDF
                File.WriteAllBytes(FinalPDF, ms.ToArray());
            }
    }