部署 MEF 部件

Question

我构建了一个可执行 shell，它使用 MEF 加载程序集（MEF 部件）并根据加载的功能进行显示/操作。

我现在想要将此应用程序部署为 ClickOnce 安装。有没有人有这方面的策略，目前我已经看到了两种策略。

1. 构建和安装部件并将其作为重新分发组件添加到 shell 应用程序 - 这意味着这两个安装基本上焊接在一起，这意味着 MEF 基本上没有意义

2. 在 shell 中构建一个下载器功能，这再次意味着每个 MEF 部分都需要在我们开始之前就知道，这使得 MEF 毫无意义。

还有其他人知道其他方法吗？我可以以相反的方式构建依赖关系，以便 MEF 部件的 clickonce 安装程序知道它应该使用什么 shell 吗？

谢谢

Answer 1

我所做的是使用 Packaging API 并制作一个映射到 shell UI 的自定义文件扩展名。它所做的只是将包解压缩到 ProgramData\MyApp\Extensions 文件夹。然后，当应用程序重新启动时，该部分就会显示出来。

请参阅此博文了解更多信息

           ' Open the Package.
        ' ('using' statement insures that 'package' is
        '  closed and disposed when it goes out of scope.)
        Using package As Package = package.Open(fileName, FileMode.Open, FileAccess.Read)
            tFolder = IO.Path.Combine(tFolder,
                MediaToolz.SharedServices.FileSystem.GetSafeFileName(package.PackageProperties.Title))

            Dim directoryInfo As New DirectoryInfo(tFolder)
            If directoryInfo.Exists Then
                directoryInfo.Delete(True)
            End If
            directoryInfo.Create()

            For Each part In package.GetParts()
                If part.ContentType = Packages.MediaToolzAddinMimeType Then
                    ExtractPart(part, tFolder)
                End If
            Next

            package.Close()
        End Using


'  --------------------------- ExtractPart ---------------------------
''' <summary>
'''   Extracts a specified package part to a target folder.</summary>
''' <param name="packagePart">
'''   The package part to extract.</param>
''' <param name="targetDirectory">
'''   The relative path from the 'current' directory
'''   to the targer folder.</param>
Private Shared Sub ExtractPart(ByVal packagePart As PackagePart, ByVal targetDirectory As String)
    ' Create a string with the full path to the target directory.
    Dim pathToTarget As String = targetDirectory
    If pathToTarget.EndsWith(IO.Path.DirectorySeparatorChar) = False Then pathToTarget += IO.Path.DirectorySeparatorChar
    ' Remove leading slash from the Part Uri,
    '   and make a new Uri from the result
    Dim stringPart As String = packagePart.Uri.ToString().TrimStart("/"c)
    ' I added this line to take off the content pat
    stringPart = IO.Path.GetFileName(stringPart)

    Dim partUri As New Uri(stringPart, UriKind.Relative)

    ' Create a full Uri to the Part based on the Package Uri
    Dim uriFullPartPath As New Uri(New Uri(pathToTarget, UriKind.Absolute), partUri)

    ' Create the necessary Directories based on the Full Part Path
    'Directory.CreateDirectory(Path.GetDirectoryName(uriFullPartPath.LocalPath))

    ' Create the file with the Part content
    Using fileStream As New FileStream(uriFullPartPath.LocalPath, FileMode.Create)
        CopyStream(packagePart.GetStream(), fileStream)
    End Using 'Close & dispose fileStream.
End Sub

'  --------------------------- CopyStream ---------------------------
''' <summary>
'''   Copies data from a source stream to a target stream.</summary>
''' <param name="source">
'''   The source stream to copy from.</param>
''' <param name="target">
'''   The destination stream to copy to.</param>
Private Shared Sub CopyStream(ByVal source As Stream, ByVal target As Stream)
    Const bufSize As Integer = &H1000
    Dim buf(bufSize - 1) As Byte
    Dim bytesRead As Integer = 0
    bytesRead = source.Read(buf, 0, bufSize)
    Do While bytesRead > 0
        target.Write(buf, 0, bytesRead)
        bytesRead = source.Read(buf, 0, bufSize)
    Loop
End Sub