How to Merge Two PDF Byte Arrays in C# Using IronPDF

using IronPdf;
using System.IO;  // For MemoryStream
using System.Threading.Tasks;
using System.Collections.Generic;  // For List operations
using System.Linq;  // For LINQ transformations

Imports IronPdf
Imports System.IO  ' For MemoryStream
Imports System.Threading.Tasks
Imports System.Collections.Generic  ' For List operations
Imports System.Linq  ' For LINQ transformations

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

var PDF = PdfDocument.Merge(
    PdfDocument.FromBytes(pdfBytes1),
    PdfDocument.FromBytes(pdfBytes2));

Dim PDF = PdfDocument.Merge( _
    PdfDocument.FromBytes(pdfBytes1), _
    PdfDocument.FromBytes(pdfBytes2))

public byte[] MergePdfByteArrays(byte[] firstPdf, byte[] secondPdf)
{
    // Load the first PDF file from byte array
    var pdf1 = new PdfDocument(firstPdf);
    // Load the second PDF file from byte array
    var pdf2 = new PdfDocument(secondPdf);
    // Merge PDF documents into one PDF
    var mergedPdf = PdfDocument.Merge(pdf1, pdf2);
    // Return the combined PDF as byte array
    return mergedPdf.BinaryData;
}

Public Function MergePdfByteArrays(firstPdf As Byte(), secondPdf As Byte()) As Byte()
    ' Load the first PDF file from byte array
    Dim pdf1 = New PdfDocument(firstPdf)
    ' Load the second PDF file from byte array
    Dim pdf2 = New PdfDocument(secondPdf)
    ' Merge PDF documents into one PDF
    Dim mergedPdf = PdfDocument.Merge(pdf1, pdf2)
    ' Return the combined PDF as byte array
    Return mergedPdf.BinaryData
End Function

public async Task<byte[]> MergePdfByteArraysAsync(byte[] firstPdf, byte[] secondPdf)
{
    return await Task.Run(() =>
    {
        var pdf1 = new PdfDocument(firstPdf);
        var pdf2 = new PdfDocument(secondPdf);
        var PDF = PdfDocument.Merge(pdf1, pdf2);
        return PDF.BinaryData;
    });
}

Imports System.Threading.Tasks

Public Class PdfMerger
    Public Async Function MergePdfByteArraysAsync(firstPdf As Byte(), secondPdf As Byte()) As Task(Of Byte())
        Return Await Task.Run(Function()
                                  Dim pdf1 = New PdfDocument(firstPdf)
                                  Dim pdf2 = New PdfDocument(secondPdf)
                                  Dim PDF = PdfDocument.Merge(pdf1, pdf2)
                                  Return PDF.BinaryData
                              End Function)
    End Function
End Class

public byte[] MergeMultiplePdfByteArrays(List<byte[]> pdfByteArrays)
{
    if (pdfByteArrays == null || pdfByteArrays.Count == 0)
        return null;

    // Convert all byte arrays to PdfDocument objects
    var pdfDocuments = pdfByteArrays
        .Select(bytes => new PdfDocument(bytes))
        .ToList();

    // Merge all PDFs in one operation
    var PDF = PdfDocument.Merge(pdfDocuments);

    // Clean up resources
    foreach (var pdfDoc in pdfDocuments)
    {
        pdfDoc.Dispose();
    }

    return PDF.BinaryData;
}

Imports System.Collections.Generic
Imports System.Linq

Public Function MergeMultiplePdfByteArrays(pdfByteArrays As List(Of Byte())) As Byte()
    If pdfByteArrays Is Nothing OrElse pdfByteArrays.Count = 0 Then
        Return Nothing
    End If

    ' Convert all byte arrays to PdfDocument objects
    Dim pdfDocuments = pdfByteArrays _
        .Select(Function(bytes) New PdfDocument(bytes)) _
        .ToList()

    ' Merge all PDFs in one operation
    Dim PDF = PdfDocument.Merge(pdfDocuments)

    ' Clean up resources
    For Each pdfDoc In pdfDocuments
        pdfDoc.Dispose()
    Next

    Return PDF.BinaryData
End Function

public byte[] SafeMergePdfByteArrays(byte[] firstPdf, byte[] secondPdf)
{
    try
    {
        // Validate input PDFs
        if (firstPdf == null || firstPdf.Length == 0)
            throw new ArgumentException("First PDF is empty");
        if (secondPdf == null || secondPdf.Length == 0)
            throw new ArgumentException("Second PDF is empty");

        using (var pdf1 = new PdfDocument(firstPdf))
        using (var pdf2 = new PdfDocument(secondPdf))
        {
            // Check for password protection
            if (pdf1.IsPasswordProtected || pdf2.IsPasswordProtected)
                throw new InvalidOperationException("Password-protected PDFs require authentication");

            var mergedPdf = PdfDocument.Merge(pdf1, pdf2);

            // Apply security settings if needed
            mergedPdf.SecuritySettings.AllowUserPrinting = true;
            mergedPdf.SecuritySettings.AllowUserCopyPasteContent = false;

            return mergedPdf.BinaryData;
        }
    }
    catch (Exception ex)
    {
        // Log error details for debugging
        Console.WriteLine($"PDF merge failed: {ex.Message}");
        throw;
    }
}

Imports System

Public Function SafeMergePdfByteArrays(firstPdf As Byte(), secondPdf As Byte()) As Byte()
    Try
        ' Validate input PDFs
        If firstPdf Is Nothing OrElse firstPdf.Length = 0 Then
            Throw New ArgumentException("First PDF is empty")
        End If
        If secondPdf Is Nothing OrElse secondPdf.Length = 0 Then
            Throw New ArgumentException("Second PDF is empty")
        End If

        Using pdf1 As New PdfDocument(firstPdf)
            Using pdf2 As New PdfDocument(secondPdf)
                ' Check for password protection
                If pdf1.IsPasswordProtected OrElse pdf2.IsPasswordProtected Then
                    Throw New InvalidOperationException("Password-protected PDFs require authentication")
                End If

                Dim mergedPdf = PdfDocument.Merge(pdf1, pdf2)

                ' Apply security settings if needed
                mergedPdf.SecuritySettings.AllowUserPrinting = True
                mergedPdf.SecuritySettings.AllowUserCopyPasteContent = False

                Return mergedPdf.BinaryData
            End Using
        End Using
    Catch ex As Exception
        ' Log error details for debugging
        Console.WriteLine($"PDF merge failed: {ex.Message}")
        Throw
    End Try
End Function