VB.Net将多个pdf合并为一个并导出

发布时间：2020-12-17 00:03:05 所属栏目：大数据来源：网络整理

导读：我必须将多个PDF合并为一个PDF. 我正在使用iText.sharp库,并收集转换代码并尝试使用它(从here) 实际代码在C#中,我将其转换为VB.NET. Private Function MergeFiles(ByVal sourceFiles As List(Of Byte())) As Byte() Dim mergedPdf As Byte() = Nothing Using

我必须将多个PDF合并为一个PDF.

我正在使用iText.sharp库,并收集转换代码并尝试使用它(从here)
实际代码在C#中,我将其转换为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：

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：

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

为什么会发生这种错误？

我有一个控制台,监视指定文件夹中的单个文件夹,然后需要将该文件夹中的所有pdf合并为一个pdf.我传递一个文件路径数组作为字符串和我想要的输出文件.

这是我使用的功能.

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)

            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,-1.0F,1.0F,reader.GetPageSizeWithRotation(i).Height)
                    ElseIf rotation = 270 Then
                        cb.AddTemplate(page,reader.GetPageSizeWithRotation(i).Width + 60,-30)
                    Else
                        cb.AddTemplate(page,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

（编辑：李大同）

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