我是使用ITextSharp的新手，正在尝试将PDF导出为附件。下面的代码工作正常

Dim pdfTemplate As String = "C:\Users\mrogers\Documents\ERCP_CA_Template2.pdf"
Dim newFile As String = "C:\Users\mrogers\Documents\ERCP_CA_Template3.pdf"
Dim pdfReader As New PdfReader(pdfTemplate)
Dim pdfStamper As New PdfStamper(pdfReader, New System.IO.FileStream(newFile, System.IO.FileMode.Create))
Dim pdfFormFields As AcroFields = pdfStamper.AcroFields

pdfFormFields.SetField("BUSINESS_SITE_ADDRESS_A5", "Demo")
pdfStamper.FormFlattening = True

pdfStamper.Close()

但是，当我尝试将其转换为导出附件时，Adobe Acrobat Reader无法打开该文件，因为该文件不受支持，或者该文件已损坏。我的代码如下。

    Dim ms As MemoryStream = New MemoryStream()
    Dim pdfTemplate As String = "C:\Users\mrogers\Documents\ERCP_CA_Template2.pdf"
    Dim pdfReader As New PdfReader(pdfTemplate)
    Dim pdfStamper As New PdfStamper(pdfReader, ms)
    Dim pdfFormFields As AcroFields = pdfStamper.AcroFields

    pdfFormFields.SetField("BUSINESS_SITE_ADDRESS_A5", "Demo")
    pdfStamper.FormFlattening = True

    HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache)
    HttpContext.Current.Response.ContentType = "application/pdf"
    HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename=testingPdf2.pdf")
    HttpContext.Current.Response.Write(ms.ToArray())
    HttpContext.Current.Response.BufferOutput = True
    HttpContext.Current.Response.Flush()
    HttpContext.Current.Response.Close()

    pdfStamper.Close()

我一直在努力寻找与此相关的任何良好示例或文档。对于我要去哪里的任何帮助，将不胜感激。