合并两个(或更多) PDF 文件

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PDFsharp seems to allow merging multiple PDF documents into one.

And the same is also possible with ITextSharp.

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最佳答案

I had to solve a similar problem and what I ended up doing was creating a small pdfmerge utility that uses the PDFSharp project which is essentially MIT licensed.

The code is dead simple, I needed a cmdline utility so I have more code dedicated to parsing the arguments than I do for the PDF merging:

using (PdfDocument one = PdfReader.Open("file1.pdf", PdfDocumentOpenMode.Import))
using (PdfDocument two = PdfReader.Open("file2.pdf", PdfDocumentOpenMode.Import))
using (PdfDocument outPdf = new PdfDocument())
{
CopyPages(one, outPdf);
CopyPages(two, outPdf);


outPdf.Save("file1and2.pdf");
}


void CopyPages(PdfDocument from, PdfDocument to)
{
for (int i = 0; i < from.PageCount; i++)
{
to.AddPage(from.Pages[i]);
}
}

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Here is a link to an example using PDFSharp and ConcatenateDocuments

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Here the solution http://www.wacdesigns.com/2008/10/03/merge-pdf-files-using-c It use free open source iTextSharp library http://sourceforge.net/projects/itextsharp

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I've done this with PDFBox. I suppose it works similarly to iTextSharp.

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You could try pdf-shuffler gtk-apps.org

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I know a lot of people have recommended PDF Sharp, however it doesn't look like that project has been updated since june of 2008. Further, source isn't available.

Personally, I've been playing with iTextSharp which has been pretty easy to work with.

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There's some good answers here already, but I thought I might mention that pdftk might be useful for this task. Instead of producing one PDF directly, you could produce each PDF you need and then combine them together as a post-process with pdftk. This could even be done from within your program using a system() or ShellExecute() call.

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Here is a single function that will merge X amount of PDFs using PDFSharp

using PdfSharp;
using PdfSharp.Pdf;
using PdfSharp.Pdf.IO;


public static void MergePDFs(string targetPath, params string[] pdfs) {
using(var targetDoc = new PdfDocument()){
foreach (var pdf in pdfs) {
using (var pdfDoc = PdfReader.Open(pdf, PdfDocumentOpenMode.Import)) {
for (var i = 0; i < pdfDoc.PageCount; i++)
targetDoc.AddPage(pdfDoc.Pages[i]);
}
}
targetDoc.Save(targetPath);
}
}

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I used iTextsharp with c# to combine pdf files. This is the code I used.

string[] lstFiles=new string[3];
lstFiles[0]=@"C:/pdf/1.pdf";
lstFiles[1]=@"C:/pdf/2.pdf";
lstFiles[2]=@"C:/pdf/3.pdf";


PdfReader reader = null;
Document sourceDocument = null;
PdfCopy pdfCopyProvider = null;
PdfImportedPage importedPage;
string outputPdfPath=@"C:/pdf/new.pdf";




sourceDocument = new Document();
pdfCopyProvider = new PdfCopy(sourceDocument, new System.IO.FileStream(outputPdfPath, System.IO.FileMode.Create));


//Open the output file
sourceDocument.Open();


try
{
//Loop through the files list
for (int f = 0; f < lstFiles.Length-1; f++)
{
int pages =get_pageCcount(lstFiles[f]);


reader = new PdfReader(lstFiles[f]);
//Add pages of current file
for (int i = 1; i <= pages; i++)
{
importedPage = pdfCopyProvider.GetImportedPage(reader, i);
pdfCopyProvider.AddPage(importedPage);
}


reader.Close();
}
//At the end save the output file
sourceDocument.Close();
}
catch (Exception ex)
{
throw ex;
}




private int get_pageCcount(string file)
{
using (StreamReader sr = new StreamReader(File.OpenRead(file)))
{
Regex regex = new Regex(@"/Type\s*/Page[^s]");
MatchCollection matches = regex.Matches(sr.ReadToEnd());


return matches.Count;
}
}

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Combining two byte[] using iTextSharp up to version 5.x:

internal static MemoryStream mergePdfs(byte[] pdf1, byte[] pdf2)
{
MemoryStream outStream = new MemoryStream();
using (Document document = new Document())
using (PdfCopy copy = new PdfCopy(document, outStream))
{
document.Open();
copy.AddDocument(new PdfReader(pdf1));
copy.AddDocument(new PdfReader(pdf2));
}
return outStream;
}

Instead of the byte[]'s it's possible to pass also Stream's

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This is something that I figured out, and wanted to share with you, using PdfSharp.

Here you can join multiple Pdfs in one, without the need of an output directory (following the input list order)

    public static byte[] MergePdf(List<byte[]> pdfs)
{
List<PdfSharp.Pdf.PdfDocument> lstDocuments = new List<PdfSharp.Pdf.PdfDocument>();
foreach (var pdf in pdfs)
{
lstDocuments.Add(PdfReader.Open(new MemoryStream(pdf), PdfDocumentOpenMode.Import));
}


using (PdfSharp.Pdf.PdfDocument outPdf = new PdfSharp.Pdf.PdfDocument())
{
for(int i = 1; i<= lstDocuments.Count; i++)
{
foreach(PdfSharp.Pdf.PdfPage page in lstDocuments[i-1].Pages)
{
outPdf.AddPage(page);
}
}


MemoryStream stream = new MemoryStream();
outPdf.Save(stream, false);
byte[] bytes = stream.ToArray();


return bytes;
}
}

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I combined the two above, because I needed to merge 3 pdfbytes and return a byte

internal static byte[] mergePdfs(byte[] pdf1, byte[] pdf2,byte[] pdf3)
{
MemoryStream outStream = new MemoryStream();
using (Document document = new Document())
using (PdfCopy copy = new PdfCopy(document, outStream))
{
document.Open();
copy.AddDocument(new PdfReader(pdf1));
copy.AddDocument(new PdfReader(pdf2));
copy.AddDocument(new PdfReader(pdf3));
}
return outStream.ToArray();
}

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Following method gets a List of byte array which is PDF byte array and then returns a byte array.

using ...;
using PdfSharp.Pdf;
using PdfSharp.Pdf.IO;


public static class PdfHelper
{
public static byte[] PdfConcat(List<byte[]> lstPdfBytes)
{
byte[] res;


using (var outPdf = new PdfDocument())
{
foreach (var pdf in lstPdfBytes)
{
using (var pdfStream = new MemoryStream(pdf))
using (var pdfDoc = PdfReader.Open(pdfStream, PdfDocumentOpenMode.Import))
for (var i = 0; i < pdfDoc.PageCount; i++)
outPdf.AddPage(pdfDoc.Pages[i]);
}


using (var memoryStreamOut = new MemoryStream())
{
outPdf.Save(memoryStreamOut, false);


res = Stream2Bytes(memoryStreamOut);
}
}


return res;
}


public static void DownloadAsPdfFile(string fileName, byte[] content)
{
var ms = new MemoryStream(content);


HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = "application/pdf";
HttpContext.Current.Response.AddHeader("content-disposition", $"attachment;filename={fileName}.pdf");
HttpContext.Current.Response.Buffer = true;
ms.WriteTo(HttpContext.Current.Response.OutputStream);
HttpContext.Current.Response.End();
}


private static byte[] Stream2Bytes(Stream input)
{
var buffer = new byte[input.Length];
using (var ms = new MemoryStream())
{
int read;
while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
ms.Write(buffer, 0, read);


return ms.ToArray();
}
}
}

So, the result of PdfHelper.PdfConcat method is passed to PdfHelper.DownloadAsPdfFile method.

PS: A NuGet package named [PdfSharp][1] need to be installed. So in the Package Manage Console window type:

Install-Package PdfSharp

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Here is a example using iTextSharp

public static void MergePdf(Stream outputPdfStream, IEnumerable<string> pdfFilePaths)
{
using (var document = new Document())
using (var pdfCopy = new PdfCopy(document, outputPdfStream))
{
pdfCopy.CloseStream = false;
try
{
document.Open();
foreach (var pdfFilePath in pdfFilePaths)
{
using (var pdfReader = new PdfReader(pdfFilePath))
{
pdfCopy.AddDocument(pdfReader);
pdfReader.Close();
}
}
}
finally
{
document?.Close();
}
}
}

The PdfReader constructor has many overloads. It's possible to replace the parameter type IEnumerable<string> with IEnumerable<Stream> and it should work as well. Please notice that the method does not close the OutputStream, it delegates that task to the Stream creator.

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Following method merges two pdfs( f1 and f2) using iTextSharp. The second pdf is appended after a specific index of f1.

 string f1 = "D:\\a.pdf";
string f2 = "D:\\Iso.pdf";
string outfile = "D:\\c.pdf";
appendPagesFromPdf(f1, f2, outfile, 3);








public static void appendPagesFromPdf(String f1,string f2, String destinationFile, int startingindex)
{
PdfReader p1 = new PdfReader(f1);
PdfReader p2 = new PdfReader(f2);
int l1 = p1.NumberOfPages, l2 = p2.NumberOfPages;




//Create our destination file
using (FileStream fs = new FileStream(destinationFile, FileMode.Create, FileAccess.Write, FileShare.None))
{
Document doc = new Document();


PdfWriter w = PdfWriter.GetInstance(doc, fs);
doc.Open();
for (int page = 1; page <= startingindex; page++)
{
doc.NewPage();
w.DirectContent.AddTemplate(w.GetImportedPage(p1, page), 0, 0);
//Used to pull individual pages from our source


}//  copied pages from first pdf till startingIndex
for (int i = 1; i <= l2;i++)
{
doc.NewPage();
w.DirectContent.AddTemplate(w.GetImportedPage(p2, i), 0, 0);
}// merges second pdf after startingIndex
for (int i = startingindex+1; i <= l1;i++)
{
doc.NewPage();
w.DirectContent.AddTemplate(w.GetImportedPage(p1, i), 0, 0);
}// continuing from where we left in pdf1


doc.Close();
p1.Close();
p2.Close();


}
}

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To solve a similar problem i used iTextSharp like this:

//Create the document which will contain the combined PDF's
Document document = new Document();


//Create a writer for de document
PdfCopy writer = new PdfCopy(document, new FileStream(OutPutFilePath, FileMode.Create));
if (writer == null)
{
return;
}


//Open the document
document.Open();


//Get the files you want to combine
string[] filePaths = Directory.GetFiles(DirectoryPathWhereYouHaveYourFiles);
foreach (string filePath in filePaths)
{
//Read the PDF file
using (PdfReader reader = new PdfReader(vls_FilePath))
{
//Add the file to the combined one
writer.AddDocument(reader);
}
}


//Finally close the document and writer
writer.Close();
document.Close();