Insert page into existing PDF using itextsharp

Question

We are using itextsharp to create a single PDF from multiple PDF files. How do I insert a new page into a PDF file that has multiple pages already in the file? When I use add page it is overwriting the existing pages and only saves the 1 page that was selected.

Here is the code that I am using to add the page to the existing PDF:

PdfReader reader = new PdfReader(sourcePdfPath);
                Document document = new Document(reader.GetPageSizeWithRotation(1));
                PdfCopy pdfCopy = new PdfCopy(document, new System.IO.FileStream(outputPdfPath, System.IO.FileMode.Create));
                MemoryStream memoryStream = new MemoryStream();
                PdfWriter writer = PdfWriter.GetInstance(document, memoryStream);
                document.AddDocListener(writer);
                document.Open();

                for (int p = 1; p <= reader.NumberOfPages; p++)
                {
                    if (pagesToExtract.FindIndex(s => s == p) == -1) continue;
                    document.SetPageSize(reader.GetPageSize(p));
                    document.NewPage();
                    PdfContentByte cb = writer.DirectContent;
                    PdfImportedPage pageImport = writer.GetImportedPage(reader, p);

                    int rot = reader.GetPageRotation(p);
                    if (rot == 90 || rot == 270)
                    {
                        cb.AddTemplate(pageImport, 0, -1.0F, 1.0F, 0, 0, reader.GetPageSizeWithRotation(p).Height);
                    }
                    else
                    {
                        cb.AddTemplate(pageImport, 1.0F, 0, 0, 1.0F, 0, 0);
                    }

                    pdfCopy.AddPage(pageImport);
                }

                pdfCopy.Close();

Answer 1

This code works. You need to have a different file to output the results.

private static void AppendToDocument(string sourcePdfPath1, string sourcePdfPath2, string outputPdfPath)
{
    using (var sourceDocumentStream1 = new FileStream(sourcePdfPath1, FileMode.Open))
    {
        using (var sourceDocumentStream2 = new FileStream(sourcePdfPath2, FileMode.Open))
        {
            using (var destinationDocumentStream = new FileStream(outputPdfPath, FileMode.Create))
            {
                var pdfConcat = new PdfConcatenate(destinationDocumentStream);
                var pdfReader = new PdfReader(sourceDocumentStream1);

                var pages = new List<int>();
                for (int i = 0; i < pdfReader.NumberOfPages; i++)
                {
                    pages.Add(i);
                }

                pdfReader.SelectPages(pages);
                pdfConcat.AddPages(pdfReader);

                pdfReader = new PdfReader(sourceDocumentStream2);

                pages = new List<int>();
                for (int i = 0; i < pdfReader.NumberOfPages; i++)
                {
                    pages.Add(i);
                }

                pdfReader.SelectPages(pages);
                pdfConcat.AddPages(pdfReader);

                pdfReader.Close();
                pdfConcat.Close();
            }
        }
    }
}

Answer 2

I've tried this code, and it works for me, but don't forget to do some validations of the number of pages and existence of the paths you use

here is the code:

private static void AppendToDocument(string sourcePdfPath, string outputPdfPath, List<int> neededPages)
    {

        var sourceDocumentStream = new FileStream(sourcePdfPath, FileMode.Open);
        var destinationDocumentStream = new FileStream(outputPdfPath, FileMode.Create);
        var pdfConcat = new PdfConcatenate(destinationDocumentStream);

        var pdfReader = new PdfReader(sourceDocumentStream);
        pdfReader.SelectPages(neededPages);
        pdfConcat.AddPages(pdfReader);

        pdfReader.Close();
        pdfConcat.Close();
    }