Question

我正在使用MVC3和MEF创建一个Web应用程序。我正在尝试使用IDNumber将我的HostModel导出到插件，然后使用该IDNumber将插件重定向到链接。我的模型没有正确导出，然后我的视图也没有从插件控制器读取模型（我通过制作测试模型对象并将其传递给视图来测试它）。我很确定我有一些混淆我如何导出到我的插件中的视图。我使用的是.aspx文件而不是.vbhtml，因为VS2010没有给我这个选项。当我尝试将.vbhtml文件拖到项目中时，它无法正常工作。

这是我的HostController：

<Export(GetType(HostModel))>
<PartCreationPolicy(CreationPolicy.NonShared)>
Public Class HostController
    Inherits System.Web.Mvc.Controller


    Private m_objHost As HostModel

    Private m_IDNUmber As String
    Property IDNumber() As String
        Get
            Return m_IDNUmber
        End Get
        Set(value As String)
            m_IDNUmber = value
        End Set
    End Property


    Function Index() As ActionResult
        ViewData("Message") = "Welcome to ASP.NET MVC!"
        If m_objHost Is Nothing Then
            m_objHost = New HostModel
        End If
        Return View(m_objHost)
    End Function

    '<HttpPost()>
    Function ChangeCUNumber(model As HostModel, strIDNumber As String) As ActionResult
        ' m_IDNUmber = strIDNumber
        model.IDNumber = strIDNumber
        Return View("Index", model)
    End Function

    <HttpPost()>
    Function GoToMini(model As HostModel) As ActionResult
        m_CUNUmber = model.CUNumber
        Dim hostContollerObj As New HomeController
        hostContollerObj.CUNumber = model.IDNumber

        m_objHost = model
        Return Redirect("http://localhost:3727/miniView")
    End Function
End Class

这是我的HostModel：

Public Class HostModel
Implements IHost

Private Shared m_instance As HostModel
Private m_IDNumber As String

Public Sub New()
End Sub



Shared ReadOnly Property instance() As HostModel
    Get
        If m_instance Is Nothing Then
            m_instance = New HostModel
        End If
        Return m_instance
    End Get
End Property


Public Property IDNumber As String Implements CUCMCV_Interfaces.IHost.IDNumber
    Get
        Return m_IDNumber
    End Get
    Set(value As String)
        m_IDNumber = value
    End Set
End Property

这是我的插件控制器：

<Export(GetType(IPlugin))> _
<ExportMetadata("PluginName", "miniView")> _
<PartCreationPolicy(CreationPolicy.NonShared)> _
Public Class miniViewController
    Inherits System.Web.Mvc.Controller
    Implements IPlugin


    <Import(GetType(HostModel))>
    Private m_objHost As HostModel


    Public Function Index() As ActionResult
        Dim renderedView As ViewResult = View("~/Plugin/miniView.dll/miniView.Index.aspx", m_objHost)

        Return renderedView
    End Function

这是我的插件视图（Index.aspx）

Public Class Index
    Inherits Mvc.ViewPage




    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load


        Dim p As ImportData = New ImportData()
        Dim strMINILink As String = "http://inside/mini?ContractNumber="
        Dim strCUNumber As String = p.instance.IDNumber
        Dim strMINIURL As String = strMINILink & strIDNumber
        Response.Redirect(strMINIURL)

    End Sub

End Class

Public Class ImportData

    <Import(GetType(HostModel))>
    Property instance As HostModel

    Public Sub New()
        Dim catalog As AggregateCatalog = New AggregateCatalog()

        catalog.Catalogs.Add(New DirectoryCatalog("C:\Documents and Settings\gbv0860\My Documents\cucmConsolidatedView\CUCMCV\cucmConsolidatedView\cucmConsolidatedView\bin"))
        Dim _container As CompositionContainer = New CompositionContainer(catalog)

        Try
            _container.ComposeParts(Me)

        Catch ex As Exception
            Console.WriteLine(ex.ToString)
        End Try

    End Sub
End Class

非常感谢任何帮助！如果您需要我澄清任何事情，请告诉我！谢谢！

Answer 1

您已将<Export(GetType(HostModel))>放在实际上不是HostController的{{1}}上。这不是有效的出口。

ASP.NET MVC将按照其确切类型请求控制器，因此您应该只使用HostModel导出HostController。

<Export>可能属于<Export(GetType(HostModel))>类。而不是实现自己的单例，你应该用HostModel标记它。

然后有一个事实是你在<PartCreationPolicy(CreationPolicy.Shared)>上有一个导入，但该类也没有导出，你只需用ImportData语句自己创建它。因此，MEF永远不会看到这些实例，也不会对导入做任何事情。

最后，请注意ASP.NET MVC不会自动使用MEF来创建对象。你需要register a dependency resolver包装一个MEF容器来设置它。 MEF2中似乎有composition provider for APS.NET MVC。

MEF的导出/导入问题

1 个答案: