Merge memorystreams to one iText document - c#-4.0

Question

I have four MemoryStreams of data that I want to merge and then open the pdfDocument, without creating a single file.
It's possible to write them down to files and then merge them but that would be bad practice and that can also cause a few issues so I want to avoid that.
However, I can not find a way to merge the MemoryStreams with iText5 for .NET.
Right now, this is how I do it with files:
private static void ConcatenateDocuments()
{
var stream = new MemoryStream();
var readerFrontPage = new PdfReader(Folder + FrontPageName);
var readerDocA = new PdfReader(Folder + docA);
var readerDocB = new PdfReader(Folder + DocB);
var readerAppendix = new PdfReader(Folder + Appendix);
var pdfCopyFields = new PdfCopyFields(stream);
pdfCopyFields.AddDocument(readerFrontPage);
pdfCopyFields.AddDocument(readerDocA );
pdfCopyFields.AddDocument(readerDocB);
pdfCopyFields.AddDocument(readerAppendix);
pdfCopyFields.Close();
SavePdf(stream, FilenameReport);
}
Since I need to remove the use of files, I keep the MemoryStream's as the different parts are built from different resources. So I have references to these memorystreams.
How can this be done?

Answer 1

The error PDF header signature not found can be fixed in this case by setting the stream's Position back to 0. Since you're not getting the error Cannot access a closed Stream I'm assuming that you are already correctly setting the PdfWriter's CloseStream to false.
Below is a full working C# 2010 WinForm app targeting iTextSharp 5.1.1.0 that creates three PDFs in MemoryStreams and combines them. Since I don't have a web server handy I'm writing them to disk.
using System;
using System.Text;
using System.Windows.Forms;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
//Create three MemoryStreams
MemoryStream[] streams = { CreateDoc("Page 1"), CreateDoc("Page 2"), CreateDoc("Page 3") };
//I don't have a web server handy so I'm going to write my final MemoryStream to a byte array and then to disk
byte[] bytes;
//Create our final combined MemoryStream
using (MemoryStream finalStream = new MemoryStream())
{
//Create our copy object
PdfCopyFields copy = new PdfCopyFields(finalStream);
//Loop through each MemoryStream
foreach (MemoryStream ms in streams)
{
//Reset the position back to zero
ms.Position = 0;
//Add it to the copy object
copy.AddDocument(new PdfReader(ms));
//Clean up
ms.Dispose();
}
//Close the copy object
copy.Close();
//Get the raw bytes to save to disk
bytes = finalStream.ToArray();
}
//Write out the file to the desktop
string outputFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Combined.pdf");
using (FileStream fs = new FileStream(outputFile, FileMode.Create, FileAccess.Write, FileShare.None))
{
fs.Write(bytes, 0, bytes.Length);
}
this.Close();
}
/// <summary>
/// Helper method to create temporary documents
/// </summary>
private MemoryStream CreateDoc(string name)
{
MemoryStream ms = new MemoryStream();
using (Document doc = new Document(PageSize.LETTER))
{
using (PdfWriter writer = PdfWriter.GetInstance(doc, ms))
{
writer.CloseStream = false;
doc.Open();
doc.Add(new Paragraph(name));
doc.Close();
}
}
return ms;
}
}
}

Answer 2

While it seams the PdfReader can not take the stream, the array of the stream works.
var readerFrontPage = new PdfReader(streamFrontPage.ToArray());