VB.Net将多个pdf合并为一个并导出 [英] VB.Net Merge multiple pdfs into one and export

问题描述

我必须将多个PDF合并为一个PDF。

I have to merge multiple PDFs into a single PDF.

我正在使用iText.sharp库，并收集转换后的代码并尝试使用它（来自这里）
实际代码是在C＃和我将其转换为VB.NET。

I am using the iText.sharp library, and collect converted the code and tried to use it (from here) The actual code is in C# and I converted that to VB.NET.

 Private Function MergeFiles(ByVal sourceFiles As List(Of Byte())) As Byte()
    Dim mergedPdf As Byte() = Nothing
    Using ms As New MemoryStream()
        Using document As New Document()
            Using copy As New PdfCopy(document, ms)
                document.Open()
                For i As Integer = 0 To sourceFiles.Count - 1
                    Dim reader As New PdfReader(sourceFiles(i))
                    ' loop over the pages in that document
                    Dim n As Integer = reader.NumberOfPages
                    Dim page As Integer = 0
                    While page < n
                        page = page + 1
                        copy.AddPage(copy.GetImportedPage(reader, page))
                    End While
                Next
            End Using
        End Using
        mergedPdf = ms.ToArray()
    End Using
End Function

我现在收到以下错误：

已添加具有相同密钥的项目。

An item with the same key has already been added.

我做了一些调试，并将问题跟踪到以下几行：

I did some debugging and have tracked the problem down to the following lines:

copy.AddPage(copy.GetImportedPage(reader,
copy.AddPage(copy.GetImportedPage(reader, page)))

为什么会发生这种错误？

Why is this error happening?

推荐答案

我有一个监控个人的控制台然后，指定文件夹中的文件夹需要将该文件夹中的所有pdf合并为单个pdf。我传递一个文件路径数组s作为字符串和我想要的输出文件。

I have a console that monitors individual folders in a designated folder then needs to merge all of the pdf's in that folder into a single pdf. I pass an array of file paths as strings and the output file i would like.

这是我使用的函数。

Public Shared Function MergePdfFiles(ByVal pdfFiles() As String, ByVal outputPath As String) As Boolean
    Dim result As Boolean = False
    Dim pdfCount As Integer = 0     'total input pdf file count
    Dim f As Integer = 0    'pointer to current input pdf file
    Dim fileName As String
    Dim reader As iTextSharp.text.pdf.PdfReader = Nothing
    Dim pageCount As Integer = 0
    Dim pdfDoc As iTextSharp.text.Document = Nothing    'the output pdf document
    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
            'Open the 1st item in the array PDFFiles
            fileName = pdfFiles(f)
            reader = New iTextSharp.text.pdf.PdfReader(fileName)
            'Get page count
            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
            'Instantiate a PdfContentByte object
            cb = writer.DirectContent
            'Now loop thru the input pdfs
            While f < pdfCount
                'Declare a page counter variable
                Dim i As Integer = 0
                'Loop thru the current input pdf's pages starting at page 1
                While i < pageCount
                    i += 1
                    'Get the input page size
                    pdfDoc.SetPageSize(reader.GetPageSizeWithRotation(i))
                    'Create a new page on the output document
                    pdfDoc.NewPage()
                    'If it is the 1st page, we add bookmarks to the page
                    'Now we get the imported page
                    page = writer.GetImportedPage(reader, i)
                    'Read the imported page's rotation
                    rotation = reader.GetPageRotation(i)
                    'Then add the imported page to the PdfContentByte object as a template based on the page's rotation
                    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
                'Increment f and read the next input pdf file
                f += 1
                If f < pdfCount Then
                    fileName = pdfFiles(f)
                    reader = New iTextSharp.text.pdf.PdfReader(fileName)
                    pageCount = reader.NumberOfPages
                End If
            End While
            'When all done, we close the document so that the pdfwriter object can write it to the output file
            pdfDoc.Close()
            result = True
        End If
    Catch ex As Exception
        Return False
    End Try
    Return result
End Function

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