如何在合并 PDF 后解锁文件以进行删除

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我现在更新了代码，最后几行是：

       reader.Close();
        f++;
        if (f >= orderedList.Count) continue;
        reader = new PdfReader(targetFolder + orderedList[f]);
        // we retrieve the total number of pages
        n = reader.NumberOfPages;
        pdfNewPageFlag = true;
       reader.Close();
    }
}

并且文档已成功完成，但最终的 PDF 已损坏（我假设是因为它没有正确关闭）

作为 Word 到 PDF 转换和合并过程的一部分，我运行使用以下方法将所有 PDF 合并为 1 个超级 PDF（iTextSharp.text.pdf）：

    public void Pdfs(string targetPdf, List<string> orderedList, string targetFolder, string spSite)
    {
        var f = 0;
        // we create a reader for a certain document
        var reader = new PdfReader(targetFolder + orderedList[f]);
        // we retrieve the total number of pages
        var n = reader.NumberOfPages;
        // step 1: creation of a document-object
        var document = new iTextSharp.text.Document(reader.GetPageSizeWithRotation(1));
        
        // step 2: we create a writer that listens to the document
        var writer = PdfWriter.GetInstance(document, new FileStream(targetPdf, FileMode.Create));
        // step 3: we open the document
        document.Open();
        var cb = writer.DirectContent;
        PdfImportedPage page;
        int rotation;
        // step 4: we add content
        var pdfPageName = 0;
        var pdfNewPageFlag = true;
        while (f < orderedList.Count)
        {
            var i = 0;
            while (i < n)
            {
                i++;
                document.SetPageSize(reader.GetPageSizeWithRotation(i));
                document.NewPage();
                if (pdfNewPageFlag)
                {
                    var chapter = new iTextSharp.text.Chapter(orderedList[pdfPageName], pdfPageName + 1);
                    document.Add(chapter);
                    pdfNewPageFlag = false;
                    pdfPageName++;
                }

                page = writer.GetImportedPage(reader, i);
                rotation = reader.GetPageRotation(i);

                if (rotation == 90 || rotation == 270)
                {
                    cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);
                }
                else
                {
                    cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
                }
            }
            f++;
            if (f >= orderedList.Count) continue;
            reader = new PdfReader(targetFolder + orderedList[f]);
            // we retrieve the total number of pages
            n = reader.NumberOfPages;
            pdfNewPageFlag = true;
        }

        // step 5: we close the document
        document.Close();
    }

此方法还会在每个原始文档的开头创建一个书签。文件全部合并后，我将调用此方法删除文件：

    private static void DeletePdfs()
    {
        // Delete the files
        foreach (var file in orderedListPdfFileNames)
        {
            var newFileName = tempfolder + file;
            File.Delete(newFileName);
        }
    }

但是在尝试实际删除文件时，我看到了这个异常：

An unhandled exception of type 'System.IO.IOException' occurred in mscorlib.dll

Additional information: The process cannot access the file '\file\IT\SK\test\HrDocs\Cover.pdf' because it is being used by another process.

在 PDFs 方法中，我尝试在 document.Close() 之前和之后调用 writer.Close() 和 reader.Close()，但随后我收到消息 Cannot close a document which is already closed .

有没有人能帮我解决这个问题或为我指明正确的方向？我似乎无法弄清楚合并过程的哪一部分正在锁定文件！

Answer 1

这只是一个没有在正确位置关闭 reader 的情况。

正如 mkl 在评论中提到的，如果 document.Close() 在关闭 reader 后失败，那么我需要在之后关闭 reader。

在下面的修改中，我在创建后将每个 reader 添加到列表中，最后它们都关闭了：

    public void Pdfs(string targetPdf, List<string> orderedList, string targetFolder, string spSite)
    {
        var readerlist = new List<PdfReader>();

        var f = 0;
        // we create a reader for a certain document
        var reader = new PdfReader(targetFolder + orderedList[f]);
        readerlist.Add(reader);

        // we retrieve the total number of pages
        var n = reader.NumberOfPages;
        // step 1: creation of a document-object
        var document = new iTextSharp.text.Document(reader.GetPageSizeWithRotation(1));

        // step 2: we create a writer that listens to the document
        var writer = PdfWriter.GetInstance(document, new FileStream(targetPdf, FileMode.Create));
        // step 3: we open the document
        document.Open();
        var cb = writer.DirectContent;
        PdfImportedPage page;
        int rotation;
        // step 4: we add content
        var pdfPageName = 0;
        var pdfNewPageFlag = true;
        while (f < orderedList.Count)
        {
            var i = 0;
            while (i < n)
            {
                i++;
                document.SetPageSize(reader.GetPageSizeWithRotation(i));
                document.NewPage();
                if (pdfNewPageFlag)
                {
                    var chapter = new iTextSharp.text.Chapter(orderedList[pdfPageName], pdfPageName + 1);
                    document.Add(chapter);
                    pdfNewPageFlag = false;
                    pdfPageName++;
                }

                page = writer.GetImportedPage(reader, i);
                rotation = reader.GetPageRotation(i);

                if (rotation == 90 || rotation == 270)
                {
                    cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(i).Height);
                }
                else
                {
                    cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
                }
            }

            f++;
            if (f >= orderedList.Count) continue;
            reader = new PdfReader(targetFolder + orderedList[f]);
            readerlist.Add(reader);

            // we retrieve the total number of pages
            n = reader.NumberOfPages;
            pdfNewPageFlag = true;
        }

        // step 5: we close the document
        document.Close();

        foreach (var rdr in readerlist)
        {
            rdr.Close();
        }
    }

如何在合并 PDF 后解锁文件以进行删除

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