.net - MEF CompositionContainer 缺少 ComposeParts 扩展方法

Question

我正在尝试将部件的 MEF 组合抽象为类库类，但我在 .Net4.5 RC 中遇到问题，因为 ComposeParts 扩展方法在类库 CompositionContainer 中不可用

我做错了什么或者可能缺少参考？

WCF 服务类工作容器

<Import(GetType(IGenericModelFactory))>
Public Property ModelFactory As IGenericModelFactory

Private _mefContainer As CompositionContainer
Private _catelog As DirectoryCatalog

Public Sub New()
    _catelog = New DirectoryCatalog(".")
    _mefContainer = New CompositionContainer(_catelog)
    _mefContainer.ComposeParts(Me)
End Sub

类库 - 缺少 ComposeParts 方法

Imports System.ComponentModel.Composition.Hosting

Namespace Core.Composition

    Public Class CompositionBuilder
        Implements IComposeObjects

        Public Function CreateContainer() As CompositionContainer Implements IComposeObjects.CreateContainer
            Return Activator.CreateInstance(Of CompositionContainer)()
        End Function

        Public Sub ComposeFromDirectory(directory As String, compositionRoot As Object) Implements IComposeObjects.ComposeFromDirectory

            Dim catelog As DirectoryCatalog = Activator.CreateInstance(GetType(DirectoryCatalog), directory)
            Dim mefContainer As CompositionContainer = Activator.CreateInstance(GetType(CompositionContainer), catelog)
            mefContainer.Composeparts(compositionRoot)

        End Sub

    End Class

End Namespace

Answer 1

看起来你必须包含System.ComponentModel.Composition命名空间

Imports System.ComponentModel.Composition.Hosting
Imports System.ComponentModel.Composition

Namespace Core.Composition

    Public Class CompositionBuilder
        Implements IComposeObjects

        Public Function CreateContainer() As CompositionContainer Implements IComposeObjects.CreateContainer
            Return Activator.CreateInstance(Of CompositionContainer)()
        End Function

        Public Sub ComposeFromDirectory(directory As String, compositionRoot As Object) Implements IComposeObjects.ComposeFromDirectory

            Dim catelog As DirectoryCatalog = Activator.CreateInstance(GetType(DirectoryCatalog), directory)
            Dim mefContainer As CompositionContainer = Activator.CreateInstance(GetType(CompositionContainer), catelog)
            mefContainer.ComposeParts(compositionRoot)

        End Sub

    End Class

End Namespace