C# 多个PDF文档合并，带增加书签，两个A4合并到一页A3上

此处用到的库是Itextsharp

/// <summary>
/// 合成pdf文件
/// </summary>
/// <param name="pdffileList"></param>
/// <param name="outMergeFile"></param>
/// <param name="RemovedOldFile"></param>
public static void MergePdfFiles(this List<string> pdffileList, string outMergeFile, bool RemovedOldFile = true)
{
    byte[] bytes1;
    using (var fs1 = new FileStream(pdffileList[0], FileMode.Open)) //此处将内容从文本提取至文件流中的目的是避免文件被占用,无法删除
    {
        bytes1 = new byte[(int)fs1.Length];
        var read = fs1.Read(bytes1, 0, bytes1.Length);
        fs1.Close();
    }
    var reader = new PdfReader(bytes1);
    reader.GetPageSize(1);
    var rec = reader.GetPageSize(1);     // iTextSharp.text.Rectangle rec = new iTextSharp.text.Rectangle(1000,800);//设置样式
    var width = rec.Width; var height = rec.Height;
    using (var document = new iTextSharp.text.Document(rec, 50, 50, 50, 50)) //创建一个文档变量
    {
        var pdfWrite = PdfWriter.GetInstance(document, new FileStream(outMergeFile, FileMode.Create));   //创建该文档
        document.Open();     //打开文档
        var contentByte = pdfWrite.DirectContent;    //添加内容
        var testData = new List<Dictionary<string, object>>();
        var page = 1;
        for (var i = 0; i < pdffileList.Count; i++)
        {
            //File.Delete(fileList[i]);
            byte[] bytes;
            using (var fs = new FileStream(pdffileList[i], FileMode.Open))
            {
                bytes = new byte[(int)fs.Length];
                var read = fs.Read(bytes, 0, bytes.Length);
                fs.Close();
            }
            reader = new PdfReader(bytes);
            var pageNum = reader.NumberOfPages;//获取文档页数
            for (var j = 1; j <= pageNum; j++)
            {
                document.NewPage();
                var newPage = pdfWrite.GetImportedPage(reader, j);
                contentByte.AddTemplate(newPage, 0, 0);
                var test = new Dictionary<string, object>
                {
                    { "Action", "GoTo"}, { "Title", Path.GetFileNameWithoutExtension(pdffileList[i])+"-Sht."+j }, {"Page", $"{page} XYZ 0 0 0 " }
                };
                testData.Add(test);
                page++;
            }
            if (RemovedOldFile) File.Delete(pdffileList[i]);
        }
        pdfWrite.Outlines = testData;
        document.Close();
    }
}

此处使用的库是pdfsharp

  /// <summary>
  /// 
  /// </summary>
  /// <param name="fnOri"></param>
  /// <param name="fnCombine"></param>
  /// <returns></returns>
  public static bool CombineA4ToA3(string fnOri, string fnCombine)
  {
      var fnNew = Path.Combine(Path.GetTempPath(), Path.GetFileName(fnOri));
      using (var xf = PdfReader.Open(fnOri))
      {
          for (var i = xf.PageCount - 1; i >= 0; i--)
          {
              var curPage = xf.Pages[i];
              var min = Math.Min(curPage.Width.Millimeter, curPage.Height.Millimeter);
              var max = Math.Max(curPage.Width.Millimeter, curPage.Height.Millimeter);
              if (Math.Abs(min - 210) < 3 && Math.Abs(max - 297.0) < 3)
              {
                  if (curPage.Width > curPage.Height) continue;
                  if (curPage.Rotate == 0)
                      curPage.Rotate = 90;
                  else curPage.Rotate = curPage.Rotate % 90 == 0 ? 0 : 90;
              }
              else
              {
                  xf.Pages.Remove(curPage);
                  Console.WriteLine($"第{i + 1} 不是A4.....正在从合并中剔除....");
              }
          }
          if (xf.PageCount > 0)
          {
              xf.Save(fnNew);
              xf.Close();
          }
          else return false;
      }
      //Create the output document
      var outputDocument = new PdfDocument();
      // Show single pages
      // (Note: one page contains two pages from the source document)
      outputDocument.PageLayout = PdfPageLayout.SinglePage;
      var font = new XFont("Arial", 12, XFontStyleEx.Bold);
      var format = new XStringFormat
      {
          Alignment = XStringAlignment.Center,
          LineAlignment = XLineAlignment.Far
      };
      // Open the external document as XPdfForm object

      using (var form = XPdfForm.FromFile(fnNew))
      {
          for (var idx = 0; idx < form.PageCount; idx += 2)
          {
              // Add a new page to the output document
              var page = outputDocument.AddPage();
              page.Orientation = PageOrientation.Portrait;
              page.Size = PageSize.A3;
              double width = page.Width;
              double height = page.Height;
              var gfx = XGraphics.FromPdfPage(page);
              // Set page number (which is one-based)
              form.PageNumber = idx + 1;
              var pn = (idx + 1).ToString();
              var box = new XRect(0, 0, width, height / 2);
              // Draw the page identified by the page number like an image
              gfx.DrawImage(form, box);

              // Write document file name and page number on each page
              box.Inflate(0, -10);
              // gfx.DrawString($"- {idx + 1} -", font, XBrushes.Red, box, format);

              if (idx + 1 >= form.PageCount) continue;
              // Set page number (which is one-based)
              form.PageNumber = idx + 2;
              var pn1=(idx + 2).ToString();
              box = new XRect(0, height / 2, width, height / 2);
              // Draw the page identified by the page number like an image
              gfx.DrawImage(form, box);
              // Write document file name and page number on each page
              box.Inflate(0, -10);
              //gfx.DrawString($"- {idx + 2} -", font, XBrushes.Red, box, format);
              var bm=outputDocument.Outlines.Add(Path.GetFileNameWithoutExtension(fnCombine) + $"-SHT-{pn}", page, true, PdfOutlineStyle.Regular,
                  XColor.FromKnownColor(XKnownColor.Black));
              bm.PageDestinationType = PdfPageDestinationType.FitBH;
              bm.Top = 0;
              bm.Left = 0;
              var bm1 = outputDocument.Outlines.Add(Path.GetFileNameWithoutExtension(fnCombine) + $"-SHT-{pn1}", page, true, PdfOutlineStyle.Regular,
                  XColor.FromKnownColor(XKnownColor.Black));
              bm1.PageDestinationType = PdfPageDestinationType.FitBH;
              bm1.Top = height / 2;
              bm1.Left = 0;
          }
      }
      outputDocument.Save(fnCombine);
      File.Delete(fnNew);
      return true;
  }