Hi
check these links ...hope they will help you

https://gnaresh.wordpress.com/2010/0...to-single-pdf/
Merge Multiple File Types into One PDF in C#, VB.NET

Folow this article
c# - Combine two (or more) PDF's - Stack Overflow

Hi,
If you having many questions in your mind regarding How to merge PDF?
Please Check this Software All in One PDF Tool - Free Download I hope they will help you

Using this source code you can merge pdf in .net file -


using System;
using System.Collections.Generic;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace HelveticSolutions.PdfLibrary
{
public static class PdfMerger
{
/// <summary>
/// Merge pdf files.
/// </summary>
/// <param name="sourceFiles">PDF files being merged.</param>
/// <returns></returns>
public static byte[] MergeFiles(List<byte[]> sourceFiles)
{
Document document = new Document();
using (MemoryStream ms = new MemoryStream())
{
PdfCopy copy = new PdfCopy(document, ms);
document.Open();
int documentPageCounter = 0;

// Iterate through all pdf documents
for (int fileCounter = 0; fileCounter < sourceFiles.Count; fileCounter++)
{
// Create pdf reader
PdfReader reader = new PdfReader(sourceFiles[fileCounter]);
int numberOfPages = reader.NumberOfPages;

// Iterate through all pages
for (int currentPageIndex = 1; currentPageIndex <= numberOfPages; currentPageIndex++)
{
documentPageCounter++;
PdfImportedPage importedPage = copy.GetImportedPage(reader, currentPageIndex);
PdfCopy.PageStamp pageStamp = copy.CreatePageStamp(importedPage);

// Write header
ColumnText.ShowTextAligned(pageStamp.GetOverConten t(), Element.ALIGN_CENTER,
new Phrase("PDF Merger by Helvetic Solutions"), importedPage.Width / 2, importedPage.Height - 30,
importedPage.Width < importedPage.Height ? 0 : 1);

// Write footer
ColumnText.ShowTextAligned(pageStamp.GetOverConten t(), Element.ALIGN_CENTER,
new Phrase(String.Format("Page {0}", documentPageCounter)), importedPage.Width / 2, 30,
importedPage.Width < importedPage.Height ? 0 : 1);

pageStamp.AlterContents();

copy.AddPage(importedPage);
}

copy.FreeReader(reader);
reader.Close();
}

document.Close();
return ms.GetBuffer();
}
}
}
}

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