How can I join two PDF's using iTextSharp?

Question

I tried to do it using this tutorial as a base, but it's throwing a null reference exception at the line specified below. Should I be doing this a different way? If not, why would it throw an null reference exception (both page and cb are NOT null). Code:

        string filePath = @"c:\temp\test_new.pdf";
        string attachPath = @"c:\temp\test.pdf";

        Console.WriteLine("Begin!");
        Document d = new Document();

        if(File.Exists(filePath)){File.Delete(filePath);}

        FileStream fs = new FileStream(filePath, FileMode.Create);

        PdfWriter pw = PdfWriter.GetInstance(d, fs);
        d.Open();
        d.Add(new Paragraph("New document!  Now lets add an attachment!"));

        PdfReader pRdr = new PdfReader(new FileStream(attachPath,FileMode.Open));
        PdfReaderContentParser parser = new PdfReaderContentParser(pRdr);

        MemoryStream ms = new MemoryStream();
        PdfWriter writer = PdfWriter.GetInstance(d, ms);
        writer.Open();
        PdfContentByte cb = writer.DirectContent;
        PdfImportedPage page;
        int rotation;
        d.SetPageSize(PageSize.LETTER);
        for (int i = 1; i <= pRdr.NumberOfPages; i++)
        {
            d.NewPage();
            page = writer.GetImportedPage(pRdr, i);
            rotation = pRdr.GetPageRotation(i);
            if (rotation == 90 || rotation == 270)
            {
                cb.AddTemplate(page, 0, -1.0F, 1.0F, 0, 0, pRdr.GetPageSizeWithRotation(i).Height);
            }
            else
            {
  /*NULL EXCEPTION HERE!!!*/cb.AddTemplate(page, 1.0F, 0, 0, 1.0F, 0, 0);  //NULL EXCEPTION HERE!!!

            }
        }

are you sure in your case `page` or even `pRdr` is not null when you have the exception? — Bolu, Jan 05 '11 at 17:40
if `pRdr` were null it would error out 7 lines above wouldn't it? Both `page` and `cb` are NOT null. — Abe Miessler, Jan 05 '11 at 17:44
I am sure you can merge 2 documents in fewer lines than this... I hope my google-fu doens't fail me — Matt Ellen, Jan 05 '11 at 18:35

score 1 · Accepted Answer · answered Jan 06 '11 at 22:19

1

1) Use PdfCopy not PdfWriter. PdfWriter is for writing generated PDFs from a Document. PdfCopy is made for copying pages from A to B.

2) If you're problem is the result of an exception PLEASE post the exception. It'll remove much of the guesswork you see in the comments.

3) PdfImportedPage is just that page's contents and resources. You lose annotations (form fields and the like), bookmarks, and so forth. PdfCopy can help with some of that, but not all.

answered Jan 06 '11 at 22:19

Mark Storer

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Exception: "Object reference not set to an instance of an object." Is that different from the "Null reference exception" i mentioned in my OP? Also I am writing a PDF from some content I have and then I want to copy existing PDFs into it, not sure if that makes a difference. I'll look into using PdfCopy, stay tuned. – Abe Miessler Jan 06 '11 at 22:33

score 0 · Answer 2 · answered Jan 05 '11 at 18:44

0

OK. I might get blasted for not answering your question, but there is a simpler way to merge two PDFs: don't use iTextSharp, use iTextDotNet

I found a post on how to do it: http://alex.buayacorp.com/merge-pdf-files-with-itextdotnet-and-net.html

I remembered this because I had to do this a couple of years ago. It does work, and well.

answered Jan 05 '11 at 18:44

Matt Ellen

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Also flexibile way: http://alex.buayacorp.com/merge-pdf-files-with-itext-and-net.html – HABJAN Jan 05 '11 at 19:41

score 0 · Answer 3 · answered Nov 12 '11 at 11:51

Check out my simple embPDFUtils library, where you can configure the merging and splitting process through an XML-Configuration file. There are methods to concatenate pdf files, split them and create pdf files from images. It is free. Check it out here: http://blog.mecum.biz/2011/11/how-master-xml-and-mistress-xsd-helped-itextsharp-out-of-the-claws-of-hippi-o-cratic-chaos-huggermugger/

How can I join two PDF's using iTextSharp?

3 Answers3

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