I want to read a PDF file using itextsharp 5, and create a new PDF file with the left half of each page of the original PDF, discarding the right half. I wrote the following code, but the result is corrupt and cannot be opened with Acrobat Reader (opening it with Chrome works though). How can I make a PDF that works with Acrobat Reader?
private byte[] ObtenerMitadPdf(byte[] Contenido)
{
using (var pdfReader = new PdfReader(Contenido))
{
using (var memoryStream = new MemoryStream())
{
using (var documento = new Document())
using (var pdfWriter = PdfWriter.GetInstance(documento, memoryStream))
{
pdfWriter.CloseStream = false;
documento.Open();
for (int i = 1; i <= pdfReader.NumberOfPages; i++)
{
var pagina = pdfWriter.GetImportedPage(pdfReader, i);
var tamañoPagina = pdfReader.GetPageSizeWithRotation(i);
var nuevoTamaño = new Rectangle(tamañoPagina.Left, tamañoPagina.Bottom,
tamañoPagina.Left + (tamañoPagina.Width / 2), tamañoPagina.Top, tamañoPagina.Rotation);
if (tamañoPagina.Rotation == 90)
{
pdfWriter.DirectContent.AddTemplate(pagina, 0, -1, 1, 0, 0, tamañoPagina.Height);
}
else
{
pdfWriter.DirectContent.AddTemplate(pagina, 0, 0);
}
documento.SetPageSize(nuevoTamaño);
documento.NewPage();
}
}
return memoryStream.ToArray();
}
}
}
I finally managed to get it working!
private byte[] ObtenerMitadPdf(byte[] Contenido)
{
using (var pdfReader = new PdfReader(Contenido))
{
using (var memoryStream = new MemoryStream())
{
using (var stamper = new PdfStamper(pdfReader, memoryStream))
{
for (int i = 1; i <= pdfReader.NumberOfPages; i++)
{
var pagina = pdfReader.GetPageN(i);
var tamañoPagina = pdfReader.GetPageSizeWithRotation(i);
var mediaBox = new PdfRectangle(tamañoPagina.Left, tamañoPagina.Bottom,
tamañoPagina.Left + (tamañoPagina.Width / 2), tamañoPagina.Top, tamañoPagina.Rotation);
pagina.Put(PdfName.MEDIABOX, mediaBox);
stamper.MarkUsed(pagina);
}
}
return memoryStream.ToArray();
}
}
}
I'm trying to merge several PDFs into a single file through a list that contains their content in byte[]. When opening a document from the Byte[] list with PdfReader, the program launches the following exception: "the document has no pages". When I review the contents of the Byte[] list there are complete, but the exception is always launched.
I try to download the content of that single page separately and the generated document launches error when opening it. The division of the pdf does well because it generates each document in physical and makes it perfect for each page of the PDF.
I appreciate your help or opinions in this situation.
This is the code I use to split and merge documents:
public List<byte[]> SplitPDF(byte[] contentPdf)
{
try
{
var listBythe = new List<byte[]>();
PdfImportedPage page = null;
PdfCopy PdfCopy = null;
PdfReader reader = new PdfReader(contentPdf);
for (int numPage = 1; numPage <= reader.NumberOfPages; numPage++)
{
Document doc = new Document(PageSize.LETTER);
var mStream = new MemoryStream();
PdfCopy = new PdfCopy(doc, mStream);
doc.Open();
page = PdfCopy.GetImportedPage(reader, numPage);
PdfCopy.AddPage(page);
listBythe.Add(mStream.ToArray());
doc.Close();
}
MergePdfToPage(listBythe);
return listBythe;
}
catch (Exception ex)
{
throw ex;
}
}
private byte[] MergePdfToPage(List<byte[]>contentPage)
{
byte[] docPdfByte = null;
var ms = new MemoryStream();
using (Document doc = new Document(PageSize.LETTER))
{
PdfCopy copy = new PdfCopy(doc, ms);
doc.Open();
var num = doc.PageNumber;
foreach (var file in contentPage.ToArray())
{
using (var reader = new PdfReader(file))
{
copy.AddDocument(reader);
}
}
doc.Close();
docPdfByte = ms.ToArray();
}
return docPdfByte;
In your loop you do
Document doc = new Document(PageSize.LETTER);
var mStream = new MemoryStream();
PdfCopy = new PdfCopy(doc, mStream);
doc.Open();
page = PdfCopy.GetImportedPage(reader, numPage);
PdfCopy.AddPage(page);
listBythe.Add(mStream.ToArray());
doc.Close();
In particular you retrieve the mStream bytes before closing doc. But before doc is closed, the pdf is incomplete in mStream!
To get a complete pdf from mStream, please change the order of instructions an do
Document doc = new Document(PageSize.LETTER);
var mStream = new MemoryStream();
PdfCopy = new PdfCopy(doc, mStream);
doc.Open();
page = PdfCopy.GetImportedPage(reader, numPage);
PdfCopy.AddPage(page);
doc.Close();
listBythe.Add(mStream.ToArray());
instead.
I created something for you, hopefully it will work as well as it did for me.
Class :
public class PDFFactory
{
public PDFFactory()
{
PdfDocument = new Document(iTextSharp.text.PageSize.A4, 65, 65, 60, 60);
}
private Document _pdfDocument;
public Document PdfDocument
{
get
{
return _pdfDocument;
}
set
{
_pdfDocument = value;
}
}
private MemoryStream _pdfMemoryStream;
public MemoryStream PDFMemoryStream
{
get
{
return _pdfMemoryStream;
}
set
{
_pdfMemoryStream = value;
}
}
private string _pdfBase64;
public string PDFBase64
{
get
{
if (this.DocumentClosed)
return _pdfBase64;
else
return null;
}
set
{
_pdfBase64 = value;
}
}
private byte[] _pdfBytes;
public byte[] PDFBytes
{
get
{
if (this.DocumentClosed)
return _pdfBytes;
else
return null;
}
set
{
_pdfBytes = value;
}
}
public byte[] GetPDFBytes()
{
PDFDocument.Close();
return PDFMemoryStream.GetBuffer();
}
public void closeDocument()
{
PDFDocument.Close();
PDFBase64 = Convert.ToBase64String(this.PDFMemoryStream.GetBuffer());
PDFBytes = this.PDFMemoryStream.GetBuffer();
}
}
Service:
public byte[] ()
{
PDFFactory pdf_1 = new PDFFactory();
PDFFactory pdf_2 = new PDFFactory();
List<byte[]> sourceFiles = new List<byte[]>();
sourceFiles.Add(pdf_1.GetPDFBytes);
sourceFiles.Add(pdf_2.GetPDFBytes);
PDFFactory pdfFinal = new PDFFactory();
for (int fileCounter = 0; fileCounter <= sourceFiles.Count - 1; fileCounter += 1)
{
PdfReader reader2 = new PdfReader(sourceFiles[fileCounter]);
int numberOfPages = reader2.NumberOfPages;
for (int currentPageIndex = 1; currentPageIndex <= numberOfPages; currentPageIndex++)
{
// Determine page size for the current page
pdfFinal.PDFDocument.SetPageSize(reader2.GetPageSizeWithRotation(currentPageIndex));
// Create page
pdfFinal.PDFDocument.NewPage();
PdfImportedPage importedPage = pdfFinal.PDFWriter.GetImportedPage(reader2, currentPageIndex);
// Determine page orientation
int pageOrientation = reader2.GetPageRotation(currentPageIndex);
if ((pageOrientation == 90) || (pageOrientation == 270))
pdfFinal.PDFWriter.DirectContent.AddTemplate(importedPage, 0, -1.0F, 1.0F, 0, 0, reader2.GetPageSizeWithRotation(currentPageIndex).Height);
else
pdfFinal.PDFWriter.DirectContent.AddTemplate(importedPage, 1.0F, 0, 0, 1.0F, 0, 0);
}
}
pdfFinal.closeDocument();
return pdfFinal.PDFBytes;
}
Let me know if it helped.
Using iTextSharp, I was able to read a base64 string and convert certain pages into local files using a FileStream. I want to do the same without saving to the local filesystem, using MemoryStream and only returning the selected pages to the calling function as a base64 string.
// function takes reader and start and end page and destination file path as parameter.
public static void ExtractPages(PdfReader pdfReader, string sourcePdfPath,
string outputPdfPath, int startPage, int endPage)
{
PdfReader reader = null;
Document sourceDocument = null;
PdfCopy pdfCopyProvider = null;
PdfImportedPage importedPage = null;
try
{
reader = pdfReader;
sourceDocument = new Document(reader.GetPageSizeWithRotation(startPage));
// old code to save selected pdf into local file system.
FileStream fileStream = new FileStream(outputPdfPath, FileMode.Create);
// memory stream created but not been used yet!
MemoryStream memoryStream = new MemoryStream();
pdfCopyProvider = new PdfCopy(sourceDocument, fileStream);
sourceDocument.Open();
// save selected page into local file system
for (int i = startPage; i <= endPage; i++)
{
importedPage = pdfCopyProvider.GetImportedPage(reader, i);
pdfCopyProvider.AddPage(importedPage);
}
#region TestMemoryStream
// TODO: New code to be added and return selected page data as bas64 string
#endregion
sourceDocument.Close();
reader.Close();
}
catch (Exception ex)
{
throw ex;
}
}
I was able to sort out the issue, my modified code is below.
reader = pdfReader;
sourceDocument = new Document(reader.GetPageSizeWithRotation(startPage));
//FileStream fileStream = new FileStream(outputPdfPath, FileMode.Create);
MemoryStream memoryStream = new MemoryStream();
pdfCopyProvider = new PdfCopy(sourceDocument, memoryStream);
sourceDocument.Open();
for (int i = startPage; i <= endPage; i++)
{
importedPage = pdfCopyProvider.GetImportedPage(reader, i);
pdfCopyProvider.AddPage(importedPage);
}
sourceDocument.Close();
reader.Close();
byte[] content1 = memoryStream.ToArray();
// var bas64 = Convert.ToBase64String(content1);
string bas64New = Convert.ToBase64String(content1);
How would I merge several pdf pages into one with iTextSharp which also supports merging pages having form elements like textboxes, checkboxes, etc.
I have tried so many by googling, but nothing has worked well.
See my answer here Merging Memory Streams. I give an example of how to merge PDFs with itextsharp.
For updating form field names add this code that uses the stamper to change the form field names.
/// <summary>
/// Merges pdf files from a byte list
/// </summary>
/// <param name="files">list of files to merge</param>
/// <returns>memory stream containing combined pdf</returns>
public MemoryStream MergePdfForms(List<byte[]> files)
{
if (files.Count > 1)
{
string[] names;
PdfStamper stamper;
MemoryStream msTemp = null;
PdfReader pdfTemplate = null;
PdfReader pdfFile;
Document doc;
PdfWriter pCopy;
MemoryStream msOutput = new MemoryStream();
pdfFile = new PdfReader(files[0]);
doc = new Document();
pCopy = new PdfSmartCopy(doc, msOutput);
pCopy.PdfVersion = PdfWriter.VERSION_1_7;
doc.Open();
for (int k = 0; k < files.Count; k++)
{
for (int i = 1; i < pdfFile.NumberOfPages + 1; i++)
{
msTemp = new MemoryStream();
pdfTemplate = new PdfReader(files[k]);
stamper = new PdfStamper(pdfTemplate, msTemp);
names = new string[stamper.AcroFields.Fields.Keys.Count];
stamper.AcroFields.Fields.Keys.CopyTo(names, 0);
foreach (string name in names)
{
stamper.AcroFields.RenameField(name, name + "_file" + k.ToString());
}
stamper.Close();
pdfFile = new PdfReader(msTemp.ToArray());
((PdfSmartCopy)pCopy).AddPage(pCopy.GetImportedPage(pdfFile, i));
pCopy.FreeReader(pdfFile);
}
}
pdfFile.Close();
pCopy.Close();
doc.Close();
return msOutput;
}
else if (files.Count == 1)
{
return new MemoryStream(files[0]);
}
return null;
}
Here is my simplified version of Jonathan's Merge code with namespaces added, and stamping removed.
public IO.MemoryStream MergePdfForms(System.Collections.Generic.List<byte[]> files)
{
if (files.Count > 1) {
using (System.IO.MemoryStream msOutput = new System.IO.MemoryStream()) {
using (iTextSharp.text.Document doc = new iTextSharp.text.Document()) {
using (iTextSharp.text.pdf.PdfSmartCopy pCopy = new iTextSharp.text.pdf.PdfSmartCopy(doc, msOutput) { PdfVersion = iTextSharp.text.pdf.PdfWriter.VERSION_1_7 }) {
doc.Open();
foreach (byte[] oFile in files) {
using (iTextSharp.text.pdf.PdfReader pdfFile = new iTextSharp.text.pdf.PdfReader(oFile)) {
for (i = 1; i <= pdfFile.NumberOfPages; i++) {
pCopy.AddPage(pCopy.GetImportedPage(pdfFile, i));
pCopy.FreeReader(pdfFile);
}
}
}
}
}
return msOutput;
}
} else if (files.Count == 1) {
return new System.IO.MemoryStream(files[0]);
}
return null;
}
to merge PDF see "Merging two pdf pages into one using itextsharp"
Below is my code for pdf merging.Thanks Jonathan for giving suggestion abt renaming fields,which resolved the issues while merging pdf pages with form fields.
private static void CombineAndSavePdf(string savePath, List<string> lstPdfFiles)
{
using (Stream outputPdfStream = new FileStream(savePath, FileMode.Create, FileAccess.Write, FileShare.None))
{
Document document = new Document();
PdfSmartCopy copy = new PdfSmartCopy(document, outputPdfStream);
document.Open();
PdfReader reader;
int totalPageCnt;
PdfStamper stamper;
string[] fieldNames;
foreach (string file in lstPdfFiles)
{
reader = new PdfReader(file);
totalPageCnt = reader.NumberOfPages;
for (int pageCnt = 0; pageCnt < totalPageCnt; )
{
//have to create a new reader for each page or PdfStamper will throw error
reader = new PdfReader(file);
stamper = new PdfStamper(reader, outputPdfStream);
fieldNames = new string[stamper.AcroFields.Fields.Keys.Count];
stamper.AcroFields.Fields.Keys.CopyTo(fieldNames, 0);
foreach (string name in fieldNames)
{
stamper.AcroFields.RenameField(name, name + "_file" + pageCnt.ToString());
}
copy.AddPage(copy.GetImportedPage(reader, ++pageCnt));
}
copy.FreeReader(reader);
}
document.Close();
}
}
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)
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]);
}
}
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);
}
}
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;
}
}
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;
}
}
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.
PDFsharp seems to allow merging multiple PDF documents into one.
And the same is also possible with ITextSharp.
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
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.
You could try pdf-shuffler gtk-apps.org
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.
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();
}
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
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();
}
}
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();
Here is a link to an example using PDFSharp and ConcatenateDocuments
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
I've done this with PDFBox. I suppose it works similarly to iTextSharp.