VB.Net Merge multiple pdfs into one and export

Question

I have to merge multiple PDFs into a single PDF.

I am using the iText.sharp library, and collect converted the code and tried to use it (from here) The actual code

Answer 1

I realize I'm pretty late to the party, but after reading the comments from @BrunoLowagie, I wanted to see if I could put something together myself that uses the examples from his linked sample chapter. It's probably overkill, but I put together some code that merges multiple PDFs into a single file that I posted on the Code Review SE site (the post, VB.NET - Error Handling in Generic Class for PDF Merge, contains the full class code). It only merges PDF files right now, but I'm planning on adding methods for additional functionality later.

The "master" method (towards the end of the Class block in the linked post, and also posted below for reference) handles the actual merging of the PDF files, but the multiple overloads provide a number of options for how to define the list of original files. So far, I've included the following features:

• The methods return a System.IO.FileInfo object if the merge is successful.
• Provide a System.IO.DirectoryInfo object or a System.String identifying a path and it will collect all PDF files in that directory (including sub-directories if specified) to merge.
• Provide a List(Of System.String) or a List(Of System.IO.FileInfo) specifying the PDFs you want to merge.
• Identify how the PDFs should be sorted before the merge (especially useful if you use one of the MergeAll methods to get all PDF files in a directory).
• If the specified output PDF file already exists, you can specify whether or not you want to overwrite it. (I'm considering adding the "ability" to automatically adjust the output PDF file's name if it already exists).
• Warning and Error properties provide a way to get feedback in the calling method, whether or not the merge is successful.

Once the code is in place, it can be used like this:

Dim PDFDir As New IO.DirectoryInfo("C:\Test Data\PDF\")
Dim ResultFile As IO.FileInfo = Nothing
Dim Merger As New PDFManipulator

ResultFile = Merger.MergeAll(PDFDir, "C:\Test Data\PDF\Merged.pdf", True, PDFManipulator.PDFMergeSortOrder.FileName, True)

Here is the "master" method. As I said, it's probably overkill (and I'm still tweaking it some), but I wanted to do my best to try to make it work as effectively as possible. Obviously it requires a Reference to the itextsharp.dll for access to the library's functions.

I've commented out the references to the Error and Warning properties of the class for this post to help reduce any confusion.

Public Function Merge(ByVal PDFFiles As List(Of System.IO.FileInfo), ByVal OutputFileName As String, ByVal OverwriteExistingPDF As Boolean, ByVal SortOrder As PDFMergeSortOrder) As System.IO.FileInfo
    Dim ResultFile As System.IO.FileInfo = Nothing
    Dim ContinueMerge As Boolean = True

    If OverwriteExistingPDF Then
        If System.IO.File.Exists(OutputFileName) Then
            Try
                System.IO.File.Delete(OutputFileName)
            Catch ex As Exception
                ContinueMerge = False

                'If Errors Is Nothing Then
                '    Errors = New List(Of String)
                'End If

                'Errors.Add("Could not delete existing output file.")

                Throw
            End Try
        End If
    End If

    If ContinueMerge Then
        Dim OutputPDF As iTextSharp.text.Document = Nothing
        Dim Copier As iTextSharp.text.pdf.PdfCopy = Nothing
        Dim PDFStream As System.IO.FileStream = Nothing
        Dim SortedList As New List(Of System.IO.FileInfo)

        Try
            Select Case SortOrder
                Case PDFMergeSortOrder.Original
                    SortedList = PDFFiles
                Case PDFMergeSortOrder.FileDate
                    SortedList = PDFFiles.OrderBy(Function(f As System.IO.FileInfo) f.LastWriteTime).ToList
                Case PDFMergeSortOrder.FileName
                    SortedList = PDFFiles.OrderBy(Function(f As System.IO.FileInfo) f.Name).ToList
                Case PDFMergeSortOrder.FileNameWithDirectory
                    SortedList = PDFFiles.OrderBy(Function(f As System.IO.FileInfo) f.FullName).ToList
            End Select

            If Not IO.Directory.Exists(New IO.FileInfo(OutputFileName).DirectoryName) Then
                Try
                    IO.Directory.CreateDirectory(New IO.FileInfo(OutputFileName).DirectoryName)
                Catch ex As Exception
                    ContinueMerge = False

                    'If Errors Is Nothing Then
                    '    Errors = New List(Of String)
                    'End If

                    'Errors.Add("Could not create output directory.")

                    Throw
                End Try
            End If

            If ContinueMerge Then
                OutputPDF = New iTextSharp.text.Document
                PDFStream = New System.IO.FileStream(OutputFileName, System.IO.FileMode.OpenOrCreate)
                Copier = New iTextSharp.text.pdf.PdfCopy(OutputPDF, PDFStream)

                OutputPDF.Open()

                For Each PDF As System.IO.FileInfo In SortedList
                    If ContinueMerge Then
                        Dim InputReader As iTextSharp.text.pdf.PdfReader = Nothing

                        Try
                            InputReader = New iTextSharp.text.pdf.PdfReader(PDF.FullName)

                            For page As Integer = 1 To InputReader.NumberOfPages
                                Copier.AddPage(Copier.GetImportedPage(InputReader, page))
                            Next page

                            If InputReader.IsRebuilt Then
                                'If Warnings Is Nothing Then
                                '    Warnings = New List(Of String)
                                'End If

                                'Warnings.Add("Damaged PDF: " & PDF.FullName & " repaired and successfully merged into output file.")
                            End If
                        Catch InvalidEx As iTextSharp.text.exceptions.InvalidPdfException
                            'Skip this file
                            'If Errors Is Nothing Then
                            '    Errors = New List(Of String)
                            'End If

                            'Errors.Add("Invalid PDF: " & PDF.FullName & " not merged into output file.")
                        Catch FormatEx As iTextSharp.text.pdf.BadPdfFormatException
                            'Skip this file
                            'If Errors Is Nothing Then
                            '    Errors = New List(Of String)
                            'End If

                            'Errors.Add("Bad PDF Format: " & PDF.FullName & " not merged into output file.")
                        Catch PassworddEx As iTextSharp.text.exceptions.BadPasswordException
                            'Skip this file
                            'If Errors Is Nothing Then
                            '    Errors = New List(Of String)
                            'End If

                            'Errors.Add("Password-protected PDF: " & PDF.FullName & " not merged into output file.")
                        Catch OtherEx As Exception
                            ContinueMerge = False
                        Finally
                            If Not InputReader Is Nothing Then
                                InputReader.Close()
                                InputReader.Dispose()
                            End If
                        End Try
                    End If
                Next PDF
            End If
        Catch ex As iTextSharp.text.pdf.PdfException
            ResultFile = Nothing
            ContinueMerge = False

            'If Errors Is Nothing Then
            '    Errors = New List(Of String)
            'End If

            'Errors.Add("iTextSharp Error: " & ex.Message)

            If System.IO.File.Exists(OutputFileName) Then
                If Not OutputPDF Is Nothing Then
                    OutputPDF.Close()
                    OutputPDF.Dispose()
                End If

                If Not PDFStream Is Nothing Then
                    PDFStream.Close()
                    PDFStream.Dispose()
                End If

                If Not Copier Is Nothing Then
                    Copier.Close()
                    Copier.Dispose()
                End If

                System.IO.File.Delete(OutputFileName)
            End If

            Throw
        Catch other As Exception
            ResultFile = Nothing
            ContinueMerge = False

            'If Errors Is Nothing Then
            '    Errors = New List(Of String)
            'End If

            'Errors.Add("General Error: " & other.Message)

            If System.IO.File.Exists(OutputFileName) Then
                If Not OutputPDF Is Nothing Then
                    OutputPDF.Close()
                    OutputPDF.Dispose()
                End If

                If Not PDFStream Is Nothing Then
                    PDFStream.Close()
                    PDFStream.Dispose()
                End If

                If Not Copier Is Nothing Then
                    Copier.Close()
                    Copier.Dispose()
                End If

                System.IO.File.Delete(OutputFileName)
            End If

            Throw
        Finally
            If Not OutputPDF Is Nothing Then
                OutputPDF.Close()
                OutputPDF.Dispose()
            End If

            If Not PDFStream Is Nothing Then
                PDFStream.Close()
                PDFStream.Dispose()
            End If

            If Not Copier Is Nothing Then
                Copier.Close()
                Copier.Dispose()
            End If

            If System.IO.File.Exists(OutputFileName) Then
                If ContinueMerge Then
                    ResultFile = New System.IO.FileInfo(OutputFileName)

                    If ResultFile.Length <= 0 Then
                        ResultFile = Nothing

                        Try
                            System.IO.File.Delete(OutputFileName)
                        Catch ex As Exception
                            Throw
                        End Try
                    End If
                Else
                    ResultFile = Nothing

                    Try
                        System.IO.File.Delete(OutputFileName)
                    Catch ex As Exception
                        Throw
                    End Try
                End If
            Else
                ResultFile = Nothing
            End If
        End Try
    End If

    Return ResultFile
End Function