Deploying MEF Parts

Question

I created an executable shell that uses MEF Parts assemblies and displays / acts according to loaded functionality.

Now I want to deploy this application as a ClickOnce installation. Someone has a strategy for this, at the moment I saw 2 strategies.

• Create and install for components and add it as a Redistributal component to the shell application - this means that 2 installations are mostly welded together, which means that MEF is basically meaningless

• Create a bootloader function in the shell, this again means that every part of the MEF must be known before we start, and make the MEF meaningless.

Does anyone else know any other approaches? Can I build the dependency in reverse order, so does the clickonce installer for the MEF parts know which shell it should use?

thanks

Answer 1

What I did, I used the packaging API and created a user-defined file extension that maps to the shell user interface. All he does is unzip the package into the ProgramData \ MyApp \ Extensions folder. Then, when the application restarts, a part appears.

See this blog for more details.

' 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