Combine two (or more) PDF's

Question

Background: I need to provide a weekly report package for my sales staff. This package contains several (5-10) crystal reports.

Problem: I would like to allow a user to run all reports and also just run a single report. I was thinking I could do this by creating the reports and then doing:

List<ReportClass> reports = new List<ReportClass>();
reports.Add(new WeeklyReport1());
reports.Add(new WeeklyReport2());
reports.Add(new WeeklyReport3());
<snip>

foreach (ReportClass report in reports)
{
    report.ExportToDisk(ExportFormatType.PortableDocFormat, @"c:\reports\" + report.ResourceName + ".pdf");
}

This would provide me a folder full of the reports, but I would like to email everyone a single PDF with all the weekly reports. So I need to combine them.

Is there an easy way to do this without install any more third party controls? I already have DevExpress & CrystalReports and I'd prefer not to add too many more.

Would it be best to combine them in the foreach loop or in a seperate loop? (or an alternate way)

Answer 1

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]);
    }
}

Answer 2

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);
    }
}

Answer 3

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;
        }           
    }