Dependency injection Mef即使项目导入到目录中也不导出

尝试在代码中进行导入，因此我尝试以下操作：

IServiceBehavior behavior = container.GetExport<IServiceBehavior>().Value;

但是，当我检查容器MefServiceBehavior（IServiceBehavior的一个实现）的局部变量时，目录中有：

container   {System.ComponentModel.Composition.Hosting.CompositionContainer}    System.ComponentModel.Composition.Hosting.CompositionContainer
    -       Catalog {MefContrib.Hosting.Generics.GenericCatalog}    System.ComponentModel.Composition.Primitives.ComposablePartCatalog  {MefContrib.Hosting.Generics.GenericCatalog}
        -       Parts   Count = 6   System.Collections.ObjectModel.ReadOnlyCollection<System.ComponentModel.Composition.Primitives.ComposablePartDefinition>
            -       [4] {MyProjectServiceLibrary.Hosting.MefServiceBehavior}    System.ComponentModel.Composition.Primitives.ComposablePartDefinition {System.ComponentModel.Composition.ReflectionModel.ReflectionComposablePartDefinition}
                -       ExportDefinitions   {System.ComponentModel.Composition.Primitives.ExportDefinition[1]}  System.Collections.Generic.IEnumerable<System.ComponentModel.Composition.Primitives.ExportDefinition> {System.ComponentModel.Composition.Primitives.ExportDefinition[]}
                    -       [System.ComponentModel.Composition.Primitives.ExportDefinition[]]   {System.ComponentModel.Composition.Primitives.ExportDefinition[1]}  System.ComponentModel.Composition.Primitives.ExportDefinition[]
                        -       [0] {MyProjectServiceLibrary.Hosting.MefServiceBehavior (ContractName="System.ServiceModel.Description.IServiceBehavior")}  System.ComponentModel.Composition.Primitives.ExportDefinition {System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition}
                            -       [System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition]    {MyProjectServiceLibrary.Hosting.MefServiceBehavior (ContractName="System.ServiceModel.Description.IServiceBehavior")}  System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition
                                -       Metadata    Count = 1   System.Collections.Generic.IDictionary<string,object> {Microsoft.Internal.Collections.ReadOnlyDictionary<string,object>}
                                    -       [0] {[ExportTypeIdentity, System.ServiceModel.Description.IServiceBehavior]}    System.Collections.Generic.KeyValuePair<string,object>
                                                Key "ExportTypeIdentity"    string
                                                Value   "System.ServiceModel.Description.IServiceBehavior"  object {string}

container{System.ComponentModel.Composition.Hosting.CompositionContainer}System.ComponentModel.Composition.Hosting.CompositionContainer
-目录{MefContrib.Hosting.Generics.GenericCatalog}System.ComponentModel.Composition.Primitives.ComponentBaltCatalog{MefContrib.Hosting.Generics.GenericCatalog}
-零件计数=6 System.Collections.ObjectModel.ReadOnlyCollection
-[4]{MyProjectServiceLibrary.Hosting.MefServiceBehavior}System.ComponentModel.Composition.Primitives.ComponentPartDefinition{System.ComponentModel.Composition.ReflectionModel.ReflectionComponentPartDefinition}
-ExportDefinitions{System.ComponentModel.Composition.Primitives.ExportDefinition[1]}System.Collections.Generic.IEnumerable{System.ComponentModel.Composition.Primitives.ExportDefinition[]}
-[System.ComponentModel.Composition.Primitives.ExportDefinition[]{System.ComponentModel.Composition.Primitives.ExportDefinition[1]}System.ComponentModel.Composition.Primitives.ExportDefinition[]
-[0]{MyProjectServiceLibrary.Hosting.MefServiceBehavior（ContractName=“System.ServiceModel.Description.IServiceBehavior”）}System.ComponentModel.Composition.Primitives.ExportDefinition{System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition}
-[System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition]{MyProjectServiceLibrary.Hosting.MefServiceBehavior（ContractName=“System.ServiceModel.Description.IServiceBehavior”）}System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition
-元数据计数=1 System.Collections.Generic.IDictionary{Microsoft.Internal.Collections.ReadOnlyDictionary}
-[0]{[ExportTypeIdentity，System.ServiceModel.Description.IServiceBehavior]}System.Collections.Generic.KeyValuePair
键“ExportTypeIdentity”字符串
值“System.ServiceModel.Description.IServiceBehavior”对象{string}

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为什么容器找不到导出。ExportTypeIdentity与异常消息中提到的相同。这是怎么回事？

我发现了一个非常有用的工具，用于调试MEF组合，名为mefx.exe，它帮助我找到了问题所在。看起来问题不在于IServiceBehavior，而在于IServiceBehavior中的一个导入，我没有将导出类型放入其中。我很高兴你解决了这个问题。我建议您通过mefx工具的链接来回答自己的问题，以帮助其他人通过搜索找到您的问题。

container   {System.ComponentModel.Composition.Hosting.CompositionContainer}    System.ComponentModel.Composition.Hosting.CompositionContainer
    -       Catalog {MefContrib.Hosting.Generics.GenericCatalog}    System.ComponentModel.Composition.Primitives.ComposablePartCatalog  {MefContrib.Hosting.Generics.GenericCatalog}
        -       Parts   Count = 6   System.Collections.ObjectModel.ReadOnlyCollection<System.ComponentModel.Composition.Primitives.ComposablePartDefinition>
            -       [4] {MyProjectServiceLibrary.Hosting.MefServiceBehavior}    System.ComponentModel.Composition.Primitives.ComposablePartDefinition {System.ComponentModel.Composition.ReflectionModel.ReflectionComposablePartDefinition}
                -       ExportDefinitions   {System.ComponentModel.Composition.Primitives.ExportDefinition[1]}  System.Collections.Generic.IEnumerable<System.ComponentModel.Composition.Primitives.ExportDefinition> {System.ComponentModel.Composition.Primitives.ExportDefinition[]}
                    -       [System.ComponentModel.Composition.Primitives.ExportDefinition[]]   {System.ComponentModel.Composition.Primitives.ExportDefinition[1]}  System.ComponentModel.Composition.Primitives.ExportDefinition[]
                        -       [0] {MyProjectServiceLibrary.Hosting.MefServiceBehavior (ContractName="System.ServiceModel.Description.IServiceBehavior")}  System.ComponentModel.Composition.Primitives.ExportDefinition {System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition}
                            -       [System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition]    {MyProjectServiceLibrary.Hosting.MefServiceBehavior (ContractName="System.ServiceModel.Description.IServiceBehavior")}  System.ComponentModel.Composition.ReflectionModel.ReflectionMemberExportDefinition
                                -       Metadata    Count = 1   System.Collections.Generic.IDictionary<string,object> {Microsoft.Internal.Collections.ReadOnlyDictionary<string,object>}
                                    -       [0] {[ExportTypeIdentity, System.ServiceModel.Description.IServiceBehavior]}    System.Collections.Generic.KeyValuePair<string,object>
                                                Key "ExportTypeIdentity"    string
                                                Value   "System.ServiceModel.Description.IServiceBehavior"  object {string}