Merge PDF Documents using .NET PDF Library

10 Jan 202324 minutes to read

Essential PDF supports merging multiple PDF documents from disk and stream.

Merging multiple documents from disk and stream

You can merge the multiple PDF document using Merge method of PdfDocumentBase class, by specifying the path of the documents in a string array.

Refer to the following code example to merge multiple documents from disk.

C#

//Creates a new PDF document.
PdfDocument finalDoc = new PdfDocument();
//Creates a string array of source files to be merged.
string[] source = { "file1.pdf", "file2.pdf" };
//Merges PDFDocument.
PdfDocument.Merge(finalDoc, source);

//Saves the final document.
finalDoc.Save("Sample.pdf");
//Closes the document.
finalDoc.Close(true);

VB.NET

'Creates a new PDF document.
Dim finalDoc As New PdfDocument()
'Creates a string array of source files to be merged.
Dim source As String() = {"file1.pdf", "file2.pdf"}
'Merges PDFDocument.
PdfDocument.Merge(finalDoc, source)

'Saves the final document.
finalDoc.Save("Sample.pdf")
'Closes the document.
finalDoc.Close(True)

UWP

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can merge specified document using the following code snippet.

//Create the file open picker.
var picker = new FileOpenPicker();
picker.FileTypeFilter.Add(".pdf");
//Browse and choose the file.
StorageFile file = await picker.PickSingleFileAsync();
//Creates an empty PDF loaded document instance.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument();
//Loads or opens an existing PDF document through Open method of PdfLoadedDocument class.
await loadedDocument.OpenAsync(file);
//Create a new PDF document.
PdfDocument document = new PdfDocument();
//Merge the document. 
PdfDocumentBase.Merge(document, loadedDocument);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
await document.SaveAsync(stream);
//Close the document.
document.Close(true);
loadedDocument.Close(true);
//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respective code samples.
Save(stream, "Sample.pdf");

ASP.NET Core

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can merge multiple documents from stream using the following code snippet.
//Creates a PDF document.
PdfDocument finalDoc = new PdfDocument();
FileStream stream1 = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
FileStream stream2 = new FileStream("file2.pdf", FileMode.Open, FileAccess.Read);
//Creates a PDF stream for merging.
Stream[] streams = { stream1, stream2 };
//Merges PDFDocument.
PdfDocumentBase.Merge(finalDoc, streams);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
finalDoc.Save(stream);
stream.Position = 0;
//Close the document.
finalDoc.Close(true);
//Disposes the streams.
stream1.Dispose();
stream2.Dispose();
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can merge multiple documents from stream using the following code snippet.
//Loads the file as stream.
Stream stream1 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file1.pdf");
Stream stream2 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file2.pdf");
//Creates a PDF stream for merging.
Stream[] source = { stream1, stream2 };
//Create a new PDF document.
PdfDocument document = new PdfDocument();            
//Merge the documents.
PdfDocumentBase.Merge(document, source);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Close the documents.
document.Close(true);
//Save the stream into PDF file.
//The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples.
if (Device.RuntimePlatform == Device.UWP)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("Sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("Sample.pdf", "application/pdf", stream);
}

You can merge the PDF document streams by using the following code example.

C#

//Creates a PDF document.
PdfDocument finalDoc = new PdfDocument();
Stream stream1 = File.OpenRead("file1.pdf");
Stream stream2 = File.OpenRead("file2.pdf");
//Creates a PDF stream for merging.
Stream[] streams = { stream1, stream2 };
//Merges PDFDocument.
PdfDocumentBase.Merge(finalDoc, streams);

//Saves the document.
finalDoc.Save("sample.pdf");
//Closes the document.
finalDoc.Close(true);
//Disposes the streams.
stream1.Dispose();
stream2.Dispose();

VB.NET

'Creates a PDF document.
Dim finalDoc As New PdfDocument()
Dim stream1 As Stream = File.OpenRead("file1.pdf")
Dim stream2 As Stream = File.OpenRead("file2.pdf")
'Creates a PDF stream for merging.
Dim streams As Stream() = {stream1, stream2}
'Merges PDFDocument.
PdfDocumentBase.Merge(finalDoc, streams)

'Saves the document.
finalDoc.Save("sample.pdf")
'Closes the document.
finalDoc.Close(True)
'Disposes the streams.
stream1.Dispose()
stream2.Dispose()

UWP

//PDF supports merging multiple documents from stream only in Windows Forms, WPF, ASP.NET, ASP.NET MVC, ASP.NET Core and Xamarin platforms. However, you can merge specified document using the following code snippet.
//Load the PDF document as stream.
Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.file1.pdf");
//Creates an empty PDF loaded document instance.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument();
//Loads or opens an existing PDF document through Open method of PdfLoadedDocument class.
await loadedDocument.OpenAsync(pdfStream);
//Create a new PDF document.
PdfDocument document = new PdfDocument();
//Merge the document.
PdfDocumentBase.Merge(document, loadedDocument);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
await document.SaveAsync(stream);
//Close the documents.
document.Close(true);
loadedDocument.Close(true);
//Save the stream as PDF document file in local machine. Refer to the PDF/UWP section for respective code samples.
Save(stream, "Sample.pdf");

ASP.NET Core

//Creates a PDF document.
PdfDocument finalDoc = new PdfDocument();
FileStream stream1 = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
FileStream stream2 = new FileStream("file2.pdf", FileMode.Open, FileAccess.Read);
//Creates a PDF stream for merging.
Stream[] streams = { stream1, stream2 };
//Merges PDFDocument.
PdfDocumentBase.Merge(finalDoc, streams);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
finalDoc.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Close the document.
finalDoc.Close(true);
//Disposes the streams.
stream1.Dispose();
stream2.Dispose();
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Loads the file as stream.
Stream stream1 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file1.pdf");
Stream stream2 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file2.pdf");
//Creates a PDF stream for merging.
Stream[] source = { stream1, stream2 };
//Create a new PDF document.
PdfDocument document = new PdfDocument();            
//Merge the documents.
PdfDocumentBase.Merge(document, source);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Close the documents.
document.Close(true);
//Save the stream into PDF file.
//The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples.
if (Device.RuntimePlatform == Device.UWP)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("Sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("Sample.pdf", "application/pdf", stream);
}

You can download a complete working sample from GitHub.

Importing pages from multiple documents

Essential PDF provides support for importing the pages from one document to another document using ImportPage method. The following code illustrates this. The imported page is added to the end of the original document.

C#

     

//Load the PDF document.
PdfLoadedDocument lDoc = new PdfLoadedDocument("file1.pdf");
//Create a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPage(lDoc, 1);

//Save the document.
document.Save("sample.pdf");
//Close the document.
document.Close(true);
lDoc.Close(true)

VB.NET

'Load the PDF document
Dim lDoc As New PdfLoadedDocument("file1.pdf")
'Creates a new document
Dim document As New PdfDocument()
'Imports the page at 1 from the lDoc
document.ImportPage(lDoc, 1)

'Save the document
document.Save("sample.pdf")
'Close the document
document.Close(True)
lDoc.Close(True)

UWP

//Create the file open picker.
var picker = new FileOpenPicker();
picker.FileTypeFilter.Add(".pdf");
//Browse and chose the file.
StorageFile file = await picker.PickSingleFileAsync();
//Creates an empty PDF loaded document instance.
PdfLoadedDocument lDoc = new PdfLoadedDocument();
//Loads or opens an existing PDF document through Open method of PdfLoadedDocument class.
await lDoc.OpenAsync(file);
//Creates a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPage(lDoc, 1);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
await document.SaveAsync(stream);
//Closes the document.
document.Close(true);
lDoc.Close(true);
//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples.
Save(stream, "sample.pdf");

ASP.NET Core

//Load the PDF document.
FileStream docStream = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
//Load the PDF document.
PdfLoadedDocument lDoc = new PdfLoadedDocument(docStream);
//Create a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPage(lDoc, 1);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Closes the document.
document.Close(true);
lDoc.Close(true);
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Load the file as stream.
Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Sample.pdf");
PdfLoadedDocument lDoc = new PdfLoadedDocument(docStream);
//Creates a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPage(lDoc, 1);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Closes the document.
document.Close(true);
lDoc.Close(true);
//Save the stream into pdf file.
//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples.
if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

You can download a complete working sample from GitHub.

You can import multiple pages from an existing document by using ImportPageRange method. The following code example illustrates this.

C#

      

//Loads PDF document.
PdfLoadedDocument lDoc = new PdfLoadedDocument("file1.pdf");
//Create a new document.
PdfDocument document = new PdfDocument();
//Imports the pages from the lDoc.
document.ImportPageRange(lDoc, 0, lDoc.Pages.Count - 1);

//Save the document.
document.Save("sample.pdf");
//Closes the documents.
document.Close(true);
lDoc.Close(true);

VB.NET

'Loads PDF document
Dim lDoc As New PdfLoadedDocument("file1.pdf")
'Creates a new document
Dim document As New PdfDocument()
'Imports the pages from the lDoc
document.ImportPageRange(lDoc, 0, lDoc.Pages.Count - 1)

'Saves the document
document.Save("sample.pdf")
'Closes the documents
document.Close(True)
lDoc.Close(True)

UWP

//Create the file open picker.
var picker = new FileOpenPicker();
picker.FileTypeFilter.Add(".pdf");
//Browse and chose the file.
StorageFile file = await picker.PickSingleFileAsync();
//Creates an empty PDF loaded document instance.
PdfLoadedDocument lDoc = new PdfLoadedDocument();
//Loads or opens an existing PDF document through Open method of PdfLoadedDocument class.
await lDoc.OpenAsync(file);
//Create a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPageRange(lDoc, 0, lDoc.Pages.Count - 1);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
await document.SaveAsync(stream);
//Closes the document.
document.Close(true);
lDoc.Close(true);
//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples.
Save(stream, "sample.pdf");

ASP.NET Core

//Load the PDF document.
FileStream docStream = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
//Load the PDF document.
PdfLoadedDocument lDoc = new PdfLoadedDocument(docStream);
//Create a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPageRange(lDoc, 0, lDoc.Pages.Count - 1);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Closes the document.
document.Close(true);
lDoc.Close(true);
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Load the file as stream.
Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file1.pdf");
PdfLoadedDocument lDoc = new PdfLoadedDocument(docStream);
//Creates a new document.
PdfDocument document = new PdfDocument();
//Imports the page at 1 from the lDoc.
document.ImportPageRange(lDoc, 0, lDoc.Pages.Count - 1);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Closes the document.
document.Close(true);
lDoc.Close(true);
//Save the stream into pdf file.
//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples.
if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

You can download a complete working sample from GitHub.

You can also import pages from multiple documents and arrange the pages by using ImportPage method. The following code example explains the same.

C#

      

//Loads document.
PdfLoadedDocument lDoc = new PdfLoadedDocument("file1.pdf");
//Loads document.
PdfLoadedDocument lDoc2 = new PdfLoadedDocument("file1.pdf");
//Create the new document.
PdfDocument document = new PdfDocument();
//Imports and arranges the pages.
document.ImportPage(lDoc, 2);
document.ImportPage(lDoc2, 1);

//Saves the document.
document.Save("sample.pdf");
//Closes the documents.
document.Close(true);
lDoc.Close(true);
lDoc2.Close(true);

VB.NET

'Loads a document
Dim lDoc As New PdfLoadedDocument("file1.pdf")
Dim lDoc2 As New PdfLoadedDocument("file2.pdf")
'create a new document
Dim document As New PdfDocument()
'imports and arranges the pages
document.ImportPage(lDoc, 2)
document.ImportPage(lDoc2, 1)

'Saves the document
document.Save("sample.pdf")
'Closes the documents
document.Close(True)
lDoc.Close(True)
lDoc2.Close(True)

UWP

//Load the PDF document as stream.
Stream pdfStream1 = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.file1.pdf");
//Creates an empty PDF loaded document instance.
PdfLoadedDocument lDoc = new PdfLoadedDocument(pdfStream1);
//Load the PDF document as stream.
Stream pdfStream2 = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.file2.pdf");
//Creates an empty PDF loaded document instance.
PdfLoadedDocument lDoc2 = new PdfLoadedDocument(pdfStream2);
//Create the new document.
PdfDocument document = new PdfDocument();
//Imports and arranges the pages.
document.ImportPage(lDoc, 2);
document.ImportPage(lDoc2, 1);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
await document.SaveAsync(stream);
//Closes the documents.
document.Close(true);
lDoc.Close(true);
lDoc2.Close(true);
//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples.
Save(stream, "sample.pdf");

ASP.NET Core

//Load the PDF document.
FileStream docStream1 = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
//Load the PDF document.
PdfLoadedDocument lDoc = new PdfLoadedDocument(docStream1);
//Load the PDF document.
FileStream docStream2 = new FileStream("file2.pdf", FileMode.Open, FileAccess.Read);
//Load the PDF document.
PdfLoadedDocument lDoc2 = new PdfLoadedDocument(docStream2);
//Create the new document.
PdfDocument document = new PdfDocument();
//Imports and arranges the pages.
document.ImportPage(lDoc, 1);
document.ImportPage(lDoc2, 0);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Closes the documents.
document.Close(true);
lDoc.Close(true);
lDoc2.Close(true);
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Load the file as stream.
Stream docStream1 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file1.pdf");
PdfLoadedDocument lDoc = new PdfLoadedDocument(docStream1);
//Load the file as stream.
Stream docStream2 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file2.pdf");
PdfLoadedDocument lDoc2 = new PdfLoadedDocument(docStream2);
//Create the new document.
PdfDocument document = new PdfDocument();
//Imports and arranges the pages.
document.ImportPage(lDoc, 1);
document.ImportPage(lDoc2, 0);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Closes the documents.
document.Close(true);
lDoc.Close(true);
lDoc2.Close(true);
//Save the stream into pdf file.
//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code sample.
if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

You can download a complete working sample from GitHub.

Best practices

Merging multiple large PDF documents can lead to high runtime memory. So, you can split the documents into multiple documents and later you can merge. This method avoids the extensive memory usage and increases the performance.

NOTE

Note: The parent PDF document has all the contents in run time memory. It releases the memory once the final PDF document instance is disposed.

You can split a large PDF document into multiple documents using Split method of PdfLoadedDocument class. The following code snippet explains this.

C#

      

//Loads the PDF document.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument("large.pdf");
//Splits the document.
loadedDocument.Split("split.pdf");
//Close the document.
loadedDocument.Close(true);

VB.NET

'Loads the PDF document
Dim loadedDocument As New PdfLoadedDocument("large.pdf")
'Splits the document
loadedDocument.Split("split.pdf")
'Close the document
loadedDocument.Close(True)

UWP

//Due to platform limitations, multiple PDF files cannot be saved to disk. So, Essential PDF supports splitting the document into multiple documents only in Windows Forms, WPF, ASP.NET, and ASP.NET MVC platforms.

ASP.NET Core

//Due to platform limitations, multiple PDF files cannot be saved to disk. So, Essential PDF supports splitting the document into multiple documents only in Windows Forms, WPF, ASP.NET, and ASP.NET MVC platforms.

Xamarin

//Due to platform limitations, multiple PDF files cannot be saved to disk. So, Essential PDF supports splitting the document into multiple documents only in Windows Forms, WPF, ASP.NET, and ASP.NET MVC platforms.

You can download a complete working sample from GitHub.

The following code shows how to merge multiple PDF documents using Merge method.

C#

//Input documents.
string[] inputDocuments = Directory.GetFiles("../../Data/Split");
//Creates a PDF document.
PdfDocument document = new PdfDocument();
//Merges the document.
PdfDocumentBase.Merge(document, inputDocuments);

//Save and close the document.
document.Save("Output.pdf");
document.Close(true);

VB.NET

'Input documents
Dim inputDocuments As String() = Directory.GetFiles("../../Data/Split")
'Create a PDF document
Dim document As New PdfDocument()
'Merges the document
PdfDocumentBase.Merge(document, inputDocuments)

'Save and close the document
document.Save("Output.pdf")
document.Close(True)

UWP

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can merge specified document using the following code snippet.
//Create the file open picker.
var picker = new FileOpenPicker();
picker.FileTypeFilter.Add(".pdf");
//Browse and choose the file.
StorageFile file = await picker.PickSingleFileAsync();
//Creates an empty PDF loaded document instance.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument();
//Loads or opens an existing PDF document through Open method of PdfLoadedDocument class.
await loadedDocument.OpenAsync(file);
//Create a new PDF document.
PdfDocument document = new PdfDocument();
//Merge the document. 
PdfDocumentBase.Merge(document, loadedDocument);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
await document.SaveAsync(stream);
//Close the documents.
document.Close(true);
loadedDocument.Close(true);
//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respective code samples.
Save(stream, "Sample.pdf");

ASP.NET Core

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can merge multiple documents from stream using the following code snippet.

//Creates a PDF document.
PdfDocument finalDoc = new PdfDocument();
//Load the PDF document.
FileStream stream1 = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
FileStream stream2 = new FileStream("file2.pdf", FileMode.Open, FileAccess.Read);
//Creates a PDF stream for merging.
Stream[] streams = { stream1, stream2 };
//Merges PDFDocument.
PdfDocumentBase.Merge(finalDoc, streams);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
finalDoc.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Close the document.
finalDoc.Close(true);
//Disposes the streams.
stream1.Dispose();
stream2.Dispose();
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can merge multiple documents from stream using the following code snippet.

//Loads the file as stream.
Stream stream1 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file1.pdf");
Stream stream2 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file2.pdf");
//Creates a PDF stream for merging.
Stream[] source = { stream1, stream2 };
//Create a new PDF document.
PdfDocument document = new PdfDocument();            
//Merge the documents.
PdfDocumentBase.Merge(document, source);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Close the documents.
document.Close(true);
//Save the stream into PDF file.
//The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples.
if (Device.RuntimePlatform == Device.UWP)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("Sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("Sample.pdf", "application/pdf", stream);
}

You can download a complete working sample from GitHub.

Optimizing PDF resources when merging PDF documents

Essential PDF provides support to optimize the PDF resources when merging PDF documents. You can optimize the resources by enabling the OptimizeResources property available in the PdfMergeOptions class.

Refer to the following code example to optimize the PDF resources when merging PDF documents.

C#

 

//Create a new PDF document.
PdfDocument finalDoc = new PdfDocument();
//Creates a string array of source files to be merged.
string[] source = { "file1.pdf", "file2.pdf" };
PdfMergeOptions mergeOptions = new PdfMergeOptions();
//Enable Optimize Resources.
mergeOptions.OptimizeResources = true;
//Merges PDFDocument.
PdfDocument.Merge(finalDoc, mergeOptions, source);

//Save the final document.
finalDoc.Save("Sample.pdf");
//Close the document.
finalDoc.Close(true);

VB.NET

'Create a new PDF document
Dim finalDoc As New PdfDocument()
'Creates a string array of source files to be merged
Dim source As String() = {"file1.pdf", "file2.pdf"}
Dim mergeOptions As New PdfMergeOptions()
'Enable Optimize Resources
mergeOptions.OptimizeResources = True
'Merges PDFDocument
PdfDocument.Merge(finalDoc, mergeOptions, source)

'Save the final document
finalDoc.Save("Sample.pdf")
'Close the document
finalDoc.Close(True)

ASP.NET Core

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can optimize PDF resources when merging multiple documents from stream using the following code snippet.
//Create a PDF document.
PdfDocument finalDoc = new PdfDocument();
//Load the PDF document.
FileStream stream1 = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
FileStream stream2 = new FileStream("file2.pdf", FileMode.Open, FileAccess.Read);
//Creates a PDF stream for merging.
Stream[] streams = { stream1, stream2 };
PdfMergeOptions mergeOptions = new PdfMergeOptions();
//Enable Optimize Resources.
mergeOptions.OptimizeResources = true;
//Merges PDFDocument.
PdfDocumentBase.Merge(finalDoc, mergeOptions, streams);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
finalDoc.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Close the document.
finalDoc.Close(true);
//Disposes the streams.
stream1.Dispose();
stream2.Dispose();
//Defining the ContentType for pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Creates a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

Xamarin

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can optimize PDF resources when merging multiple documents from stream using the following code snippet.
//Loads the file as stream.
Stream stream1 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file1.pdf");
Stream stream2 = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.file2.pdf");
//Creates a PDF stream for merging.
Stream[] source = { stream1, stream2 };
//Create a new PDF document.
PdfDocument document = new PdfDocument();
PdfMergeOptions mergeOptions = new PdfMergeOptions();
//Enable Optimize Resources.
mergeOptions.OptimizeResources = true;
//Merge the documents.
PdfDocumentBase.Merge(document, mergeOptions, source);

//Save the PDF document to stream.
MemoryStream stream = new MemoryStream();
document.Save(stream);
//Close the document.
document.Close(true);
//Save the stream into PDF file.
//The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples.
if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("Sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("Sample.pdf", "application/pdf", stream);
}

You can download a complete working sample from GitHub.

Extend the margin of the PDF pages while merging PDF document

The Syncfusion PDF library provides support for extending the margins of the pdf pages by using the ExtendMargin property available from the PdfMergeOptions class. When ExtendMargin is set to true, then a specified margin is considered while merging the existing documents.

The following code sample illustrates this.

C#

//Create a new PDF document.
PdfDocument finalDoc = new PdfDocument();
//Create new instance for the document margin.
PdfMargins margin = new PdfMargins();
margin.All = 40;
//Set margin.
finalDoc.PageSettings.Margins = margin;
//Create a string array of source files to be merged.
string[] source = { "file1.pdf", "file2.pdf" };
PdfMergeOptions mergeOptions = new PdfMergeOptions();
// Enable the Extend Margin Property.
mergeOptions.ExtendMargin=true;
//Merge PDFDocument.
PdfDocument.Merge(finalDoc, mergeOptions, source);

//Save the final document.
finalDoc.Save("Sample.pdf");
//Close the document.
finalDoc.Close(true);

VB.NET

'Create a new PDF document
Dim finalDoc As New PdfDocument()
'Create new instance for the document margin
Dim margin As PdfMargins = New PdfMargins()
margin.All = 40
'Set margin
finalDoc.PageSettings.Margins = margin
'Create a string array of source files to be merged
Dim source As String() = {"file1.pdf", "file2.pdf"}
Dim mergeOptions As New PdfMergeOptions()
'Enable the Extend Margin Property
mergeOptions.ExtendMargin=true
'Merge PDFDocument
PdfDocument.Merge(finalDoc, mergeOptions, source)

'Save the final document
finalDoc.Save("Sample.pdf")
'Close the document
finalDoc.Close(True)

ASP.NET Core

//Due to platform limitations, the PDF file cannot be loaded from disk. However, you can optimize PDF resources when merging multiple documents from a stream using the following code snippet.
//Create a PDF document.
PdfDocument finalDoc = new PdfDocument();
//Create new instance for the document margin.
PdfMargins margin= new PdfMargins();
margin.All=40;
//Set margin.
finalDoc.PageSettings.Margins = margin;
//Load the PDF document.
FileStream stream1 = new FileStream("file1.pdf", FileMode.Open, FileAccess.Read);
FileStream stream2 = new FileStream("file2.pdf", FileMode.Open, FileAccess.Read);
//Create a PDF stream for merging.
Stream[] streams = { stream1, stream2 };
PdfMergeOptions mergeOptions = new PdfMergeOptions();
//Enable the Extend Margin.
mergeOptions.ExtendMargin = true;
//Merge PDFDocument.
PdfDocumentBase.Merge(finalDoc, mergeOptions, streams);

//Save the document into stream.
MemoryStream stream = new MemoryStream();
finalDoc.Save(stream);
//Set the position as '0'.
stream.Position = 0;
//Close the document.
finalDoc.Close(true);
//Dispose the stream.
stream1.Dispose();
stream2.Dispose();
//Define the ContentType for the pdf file.
string contentType = "application/pdf";
//Define the file name.
string fileName = "sample.pdf";
//Create a FileContentResult object by using the file contents, content type, and file name.
return File(stream, contentType, fileName);

You can download a complete working sample from GitHub.