如何使用 ITextSharp 在 PDF 文件上设置密码而不下载该 PDF 文件？

Question

我使用 ASP.NET 创建一个简单的 PDF 创建应用程序。该应用程序将使用密码即时创建 PDF 文件以保护该文档。这是我的代码：

    Sub createPDFFile()
        Dim doc As Document = New Document
        PdfWriter.GetInstance(doc, New FileStream(Request.PhysicalApplicationPath + _
                              "pdf\result.pdf", FileMode.Create))
        doc.Open()
        doc.Add(New Paragraph("Hello World!! only Testing"))
        doc.Close()
        SetPDFPassword(Server.MapPath("~/pdf/result.pdf"), "resultwithpassword.pdf", "12345")
        Response.Redirect("pdf/1.pdf")
    End Sub

这是我为 PDF 文件添加密码的代码：

     Private Sub SetPDFPassword(ByVal FullPathPdfFileName As String, ByVal DownloadPDFFileName As String, ByVal ForOpenPassword As String)
        Dim sname As String = FullPathPdfFileName
        Dim sname1 As String = New System.IO.FileInfo(FullPathPdfFileName).DirectoryName & "/test.pdf"
        Dim reader As New PdfReader(sname)
        Dim n As Integer = reader.NumberOfPages

        Dim document As New Document(reader.GetPageSizeWithRotation(1))
        Dim writer As PdfWriter = PdfWriter.GetInstance(document, New IO.FileStream(sname1, IO.FileMode.Create))
        writer.SetEncryption(PdfWriter.STRENGTH128BITS, ForOpenPassword, Nothing, PdfWriter.AllowPrinting)
        document.Open()
        Dim cb As PdfContentByte = writer.DirectContent
        Dim page As PdfImportedPage
        Dim rotation As Integer
        Dim i As Integer = 0

        While i < n
            i += 1
            document.SetPageSize(reader.GetPageSizeWithRotation(i))
            document.NewPage()
            page = writer.GetImportedPage(reader, i)
            rotation = reader.GetPageRotation(i)
            If rotation = 90 OrElse rotation = 270 Then
                cb.AddTemplate(page, 0, -1.0F, 1.0F, 0, 0, _
                reader.GetPageSizeWithRotation(i).Height)
            Else
                cb.AddTemplate(page, 1.0F, 0, 0, 1.0F, 0, _
                0)

            End If
        End While

        document.Close()
        writer.Close()

        Dim PDFfile As New IO.FileStream(sname1, IO.FileMode.Open)
        Dim FileSize As Long
        FileSize = PDFfile.Length
        Dim buffer As Byte() = New Byte(CInt(FileSize) - 1) {}
        PDFfile.Read(buffer, 0, CInt(FileSize))
        PDFfile.Close()
        System.IO.File.Delete(sname1)
        Response.AddHeader("Content-Disposition", "attachment;filename=" & DownloadPDFFileName)
        Response.ContentType = "application/pdf"
        Response.BinaryWrite(buffer)
        Response.Flush()
        Response.Close()

    End Sub

该代码运行良好。它可以生成一个PDF文件并添加一些密码来打开，但PDF文件将发送给用户。有谁知道如何生成带有密码的 PDF 文件，但结果文件仍在服务器上，并且只能从网络浏览器显示（不显示下载提示）？预先感谢..:D

Answer 1

如果我错了，请纠正我，但我认为这取决于浏览器在浏览器中显示 pdf 或询问您是否要下载它。

Adobe Acrobat 插件可在 http://www.adobe.com/ 是一个帮助用户在浏览器中显示pdf的插件。

如何在安装了插件的浏览器中显示pdf：http://www.okanagan.bc.ca/administration/itservices/edtech/elearn/Configuring_the_browser_to_show_pdf_files.html