How to add a blank page to a pdf using iTextSharp?

Question

I am trying to do something I thought would be quite simple, however it is not so straight forward and google has not helped.

I am using iTextSharp to merge PDF documents (letters) together so they can all be printed at once. If a letter has an odd number of pages I need to append a blank page, so we can print the letters double-sided.

Here is the basic code I have at the moment for merging all of the letters:

// initiaise  MemoryStream pdfStreamOut = new MemoryStream();     Document document = null;     MemoryStream pdfStreamIn = null;     PdfReader reader = null;     int numPages = 0;     PdfWriter writer = null;   for int(i = 0;i < letterList.Count; i++) {     byte[] myLetterData = ...;     pdfStreamIn = new MemoryStream(myLetterData);     reader = new PdfReader(pdfStreamIn);     numPages = reader.NumberOfPages;      // open the streams to use for the iteration     if (i == 0)     {         document = new Document(reader.GetPageSizeWithRotation(1));         writer = PdfWriter.GetInstance(document, pdfStreamOut);         document.Open();     }      PdfContentByte cb = writer.DirectContent;     PdfImportedPage page;      int importedPageNumber = 0;     while (importedPageNumber < numPages)     {         importedPageNumber++;         document.SetPageSize(reader.GetPageSizeWithRotation(importedPageNumber));         document.NewPage();         page = writer.GetImportedPage(reader, importedPageNumber);         cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);     } } 

I have tried using:

    document.SetPageSize(reader.GetPageSizeWithRotation(1));     document.NewPage(); 

at the end of the for loop for an odd number of pages without success.

Answer 1

Well I was almost there. The document won't actually create the page until you put something on it, so as soon as I added an empty table, bam! It worked!

Here is the code that will add a blank page if the document I am merging has an odd number of pages:

if (numPages > 0 && numPages % 2 == 1) {     bool result = document.NewPage();     document.Add(new Table(1)); } 

If this doesn't work in newer versions, try this instead:

document.Add(new Chunk());