itextsharp change from pdfwriter to pdfstamper to keep bookmarks in PDF

I am using iTextSharp to merge PDF documents together. My problem is I am trying to merge a large PDF which contains bookmarks. My current function is using PdfWriter to merge the documents. I know PdfStamper will work, but I cannot figure out how to change the function to work properly.

When I change PdfWriter to PdfStamper in the example below I get an error.

Code Example:

writer = PdfStamper.GetInstance(pdfDoc, New FileStream(outputPath, FileMode.OpenOrCreate))

Error Message:

'GetInstance' is not a member of 'iTextSharp.text.pdf.PdfStamper'

Here is the entire function:

Public Shared Function MergePdfFiles(ByVal pdfFiles() As String, ByVal outputPath As String) As Boolean
    Dim result As Boolean = False
    Dim pdfCount As Integer = 0     
    Dim f As Integer = 0    
    Dim fName As String
    Dim reader As iTextSharp.text.pdf.PdfReader = Nothing
    Dim pageCount As Integer = 0
    Dim pdfDoc As iTextSharp.text.Document = Nothing    
    Dim writer As PdfWriter = Nothing
    Dim cb As PdfContentByte = Nothing

    Dim page As PdfImportedPage = Nothing
    Dim rotation As Integer = 0

    Try
        pdfCount = pdfFiles.Length
        If pdfCount > 1 Then
            fName = pdfFiles(f)
            reader = New iTextSharp.text.pdf.PdfReader(fName)
            pageCount = reader.NumberOfPages

            pdfDoc = New iTextSharp.text.Document(reader.GetPageSizeWithRotation(1), 18, 18, 18, 18)

            writer = PdfWriter.GetInstance(pdfDoc, New FileStream(outputPath, FileMode.OpenOrCreate))

            With pdfDoc
                .Open()
            End With
            cb = writer.DirectContent
            While f < pdfCount
                Dim i As Integer = 0
                While i < pageCount
                    i += 1
                    pdfDoc.SetPageSize(reader.GetPageSizeWithRotation(i))
                    pdfDoc.NewPage()
                    page = writer.GetImportedPage(reader, i)
                    rotation = reader.GetPageRotation(i)
                    If rotation = 90 Then
                        cb.AddTemplate(page, 0, -1.0F, 1.0F, 0, 0, reader.GetPageSizeWithRotation(i).Height)
                    ElseIf rotation = 270 Then
                        cb.AddTemplate(page, 0, 1.0F, -1.0F, 0, reader.GetPageSizeWithRotation(i).Width + 60, -30)
                    Else
                        cb.AddTemplate(page, 1.0F, 0, 0, 1.0F, 0, 0)
                    End If
                End While
                f += 1
                If f < pdfCount Then
                    fName = pdfFiles(f)
                    reader = New iTextSharp.text.pdf.PdfReader(fName)
                    pageCount = reader.NumberOfPages
                End If
            End While
            pdfDoc.Close()
            result = True
        End If
    Catch ex As Exception
        MessageBox.Show(ex.Message)
        Return False
    End Try
    Return result
End Function

Solution

You can't just change PdfWriter to PdfStamper. You need to create a stamper with a reader and an output stream:

PdfReader reader = new PdfReader(pathToSrc);
PdfStamper.GetInstance(reader, New FileStream(outputPath, FileMode.OpenOrCreate));
// do stuff
stamper.Close();

You don't need a Document instance if you use PdfStamper; you only need to read the documentation more closely.

All of the above is useless for you, because PdfStamper is the class to use when you manipulate a single file. If you want to merge different file, you need to use PdfCopy or PdfSmartCopy.

Please take a look at the ConcatenateBookmarks example. There's a C# example at the bottom of the page if you don't understand Java.

Browse the official iText website if you have further questions.