iText7迁移PDF合并函数遭遇BouncyCastle依赖错误求助

我已经用iTextSharp实现了从数据库流式读取PDF字节数组并合并的函数，代码如下：

Public Function PDF_Functions_AddPages(PDFByteContent As List(Of Byte())) As Byte()
 Try
    Using MS As New System.IO.MemoryStream
        Using vDoc As New iTextSharp.text.Document()
            Using vCopy As New PdfSmartCopy(vDoc, MS)
                vDoc.Open()
                For Each Row In PDFByteContent
                    Using vReader As New PdfReader(Row)
                        vCopy.AddDocument(vReader)
                    End Using
                Next
                vDoc.Close()
            End Using
        End Using
        Return MS.ToArray()
    End Using
Catch ex As Exception
    EmailError(ex)
    Return Nothing
End Try
End Function

但我不知道如何用iText7实现相同的功能。

更新：尝试的iText7代码及报错 #

我尝试了以下iText7代码：

Function PDF_AddPages(PDFByteContent As List(Of Byte())) As Byte()
 Try
     Using MS As New System.IO.MemoryStream
         Using vWriter As New iText.Kernel.Pdf.PdfWriter(MS)
             Using vMerged As New iText.Kernel.Pdf.PdfDocument(vWriter)
                 Dim vMerger As New iText.Kernel.Utils.PdfMerger(vMerged)
                 For Each Row In PDFByteContent
                     Using copyFromMS As New MemoryStream(Row)
                         Using vReader As New iText.Kernel.Pdf.PdfReader(copyFromMS)
                             Using copyFromDoc As New iText.Kernel.Pdf.PdfDocument(vReader)
                                 vMerger.Merge(copyFromDoc, 1, copyFromDoc.GetNumberOfPages())
                             End Using
                         End Using
                     End Using
                 Next
             End Using

         End Using
         Return MS.ToArray()
     End Using
 Catch ex As Exception
     EmailError(ex, 2226, PageName)
     Return Nothing
 End Try
 End Function

但这段代码抛出了与BouncyCastle相关的错误：

System.TypeInitializationException: The type initializer for 'iText.Bouncycastleconnector.BouncyCastleFactoryCreator' threw an exception. ---> System.IO.FileLoadException: Could not load file or assembly 'Microsoft.Extensions.Logging.Abstractions, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
  at iText.Bouncycastleconnector.BouncyCastleFactoryCreator..cctor()

……或许我离解决问题更近一步了？

内容的提问来源于stack exchange，提问作者gchq