使用 itextsharp 将页面插入现有 PDF-C#/.NET问题

Insert page into existing PDF using itextsharp(使用 itextsharp 将页面插入现有 PDF)

本文介绍了使用 itextsharp 将页面插入现有 PDF的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我们正在使用 itextsharp 从多个 PDF 文件创建一个 PDF.如何将新页面插入到文件中已有多个页面的 PDF 文件中?当我使用添加页面时，它会覆盖现有页面，并且只保存选择的 1 页.

We are using itextsharp to create a single PDF from multiple PDF files. How do I insert a new page into a PDF file that has multiple pages already in the file? When I use add page it is overwriting the existing pages and only saves the 1 page that was selected.

这是我用来将页面添加到现有 PDF 的代码:

Here is the code that I am using to add the page to the existing PDF:

PdfReader reader = new PdfReader(sourcePdfPath);
                Document document = new Document(reader.GetPageSizeWithRotation(1));
                PdfCopy pdfCopy = new PdfCopy(document, new System.IO.FileStream(outputPdfPath, System.IO.FileMode.Create));
                MemoryStream memoryStream = new MemoryStream();
                PdfWriter writer = PdfWriter.GetInstance(document, memoryStream);
                document.AddDocListener(writer);
                document.Open();

                for (int p = 1; p <= reader.NumberOfPages; p++)
                {
                    if (pagesToExtract.FindIndex(s => s == p) == -1) continue;
                    document.SetPageSize(reader.GetPageSize(p));
                    document.NewPage();
                    PdfContentByte cb = writer.DirectContent;
                    PdfImportedPage pageImport = writer.GetImportedPage(reader, p);

                    int rot = reader.GetPageRotation(p);
                    if (rot == 90 || rot == 270)
                    {
                        cb.AddTemplate(pageImport, 0, -1.0F, 1.0F, 0, 0, reader.GetPageSizeWithRotation(p).Height);
                    }
                    else
                    {
                        cb.AddTemplate(pageImport, 1.0F, 0, 0, 1.0F, 0, 0);
                    }

                    pdfCopy.AddPage(pageImport);
                }

                pdfCopy.Close();

推荐答案

此代码有效.您需要使用不同的文件来输出结果.

This code works. You need to have a different file to output the results.

private static void AppendToDocument(string sourcePdfPath1, string sourcePdfPath2, string outputPdfPath)
{
    using (var sourceDocumentStream1 = new FileStream(sourcePdfPath1, FileMode.Open))
    {
        using (var sourceDocumentStream2 = new FileStream(sourcePdfPath2, FileMode.Open))
        {
            using (var destinationDocumentStream = new FileStream(outputPdfPath, FileMode.Create))
            {
                var pdfConcat = new PdfConcatenate(destinationDocumentStream);
                var pdfReader = new PdfReader(sourceDocumentStream1);

                var pages = new List<int>();
                for (int i = 0; i < pdfReader.NumberOfPages; i++)
                {
                    pages.Add(i);
                }

                pdfReader.SelectPages(pages);
                pdfConcat.AddPages(pdfReader);

                pdfReader = new PdfReader(sourceDocumentStream2);

                pages = new List<int>();
                for (int i = 0; i < pdfReader.NumberOfPages; i++)
                {
                    pages.Add(i);
                }

                pdfReader.SelectPages(pages);
                pdfConcat.AddPages(pdfReader);

                pdfReader.Close();
                pdfConcat.Close();
            }
        }
    }
}