C# 属性必须实现接口 变量metadataAttribute= type.GetCustomAttributes（） .SelectMany( a=> a、 GetType（） .GetCustomAttributes（） 第（）类 .Concat（新的[]{a}.OfType（）） .OfType（）.SingleOrDefault（）； //如果我们找到了正确的元数据 if（metadataAttribute！=null） { //返回懒惰的工厂 返回新的KeyValuePair（类型，metadataAttribute）； } } } //来自http://www.codewrecks.com/blog/index.php/2012/05/08/getting-the-list-of-type-associated-to-a-given-export-in-mef/ 公共静态IEnumerable GetExportTypes（此CompositionContainer mefContainer） T:在哪里上课 { //查看mef目录，找出T型的所有类型 返回mefContainer.Catalog.Parts.Where（part=>part.ExportDefinitions .任何( def=> def.Metadata.ContainsKey( “ExportTypeIdentity”）&& 定义元数据[“ExportTypeIdentity”] .等于( typeof（T.FullName））） .可计算的（） .Select（part=>ReflectionModelServices.GetPartType（part）.Value）； } }

看起来您正在尝试将其用作unity容器，最好只使用unit容器。我们目前使用MEF来查找所有的注册，这些注册是带有元数据的导出属性，元数据说明了如何注册这些属性。然后执行与上面类似的操作来填充unity容器，而不是属性

你会像这样使用它

ViewModelsLazy = mefContainer.GetExportsResolved<ViewModelBase, IViewModelMetadata>(unityContainer);

ViewModelsLazy=mefContainer.GetExportsResolved（unityContainer）；

同样，使用unity容器并执行以下操作可能更好

var regs = mefContainer.GetExportTypesWithMetadata<ViewModelBase, IViewModelMetadata>();
foreach (var reg in regs)
{
    unityContainer.RegisterType(typeof (ViewModelBase), reg.Key, reg.Value.Name);
}

var regs=mefContainer.GetExportTypesWithMetadata（）；
foreach（regs中的var reg）
{
unityContainer.RegisterType（typeof（ViewModelBase）、reg.Key、reg.Value.Name）；
}

当您想要解析一个类时，您将转到unity并执行解析，将名称作为合同名称传入

unityContainer.Resolve<ViewModelsLazy.Single(v => v.Metadata.Name.Equals(viewModel)).Value>();

public static class MEFExtensions
{
    public static IEnumerable<Lazy<T, M>> GetExportsResolved<T, M>(this CompositionContainer mefContainer,
                                                                   IUnityContainer unityContainer) 
        where T: class where M: class
    {
        // wrap the resolve around unity resolve then change type to T
        return mefContainer.GetExportTypesWithMetadata<T, M>()
                           .Select(kv => new Lazy<T, M>(() => unityContainer.Resolve(kv.Key) as T, kv.Value));
    }

    public static IEnumerable<KeyValuePair<Type, M>> GetExportTypesWithMetadata<T, M>(
        this CompositionContainer mefcontainer)
        where T : class where M : class
    {

        // need to examine each type to see if they have the correct export attribute and metadata
        foreach (var type in mefcontainer.GetExportTypes<T>())
        {
            // should just be one if more than one will throw exception
            // metadata or export attribute has to implement the interface
            var metadataAttribute =
                type.GetCustomAttributes()
                    .SelectMany(
                        a =>
                        a.GetType()
                         .GetCustomAttributes()
                         .OfType<MetadataAttributeAttribute>()
                         .Concat<Attribute>(new[] { a }.OfType<ExportAttribute>()))
                    .OfType<M>().SingleOrDefault();

            // if we found the correct metadata
            if (metadataAttribute != null)
            {
                // return the lazy factory
                yield return new KeyValuePair<Type, M>(type, metadataAttribute);
            }
        }
    }

    //Idea from http://www.codewrecks.com/blog/index.php/2012/05/08/getting-the-list-of-type-associated-to-a-given-export-in-mef/
    public static IEnumerable<Type> GetExportTypes<T>(this CompositionContainer mefContainer)
        where T : class
    {
        // look in the mef catalog to grab out all the types that are of type T
        return mefContainer.Catalog.Parts.Where(part => part.ExportDefinitions
                                                            .Any(
                                                                def =>
                                                                def.Metadata.ContainsKey(
                                                                    "ExportTypeIdentity") &&
                                                                def.Metadata["ExportTypeIdentity"]
                                                                    .Equals(
                                                                        typeof (T).FullName)))
                           .AsEnumerable()
                           .Select(part => ReflectionModelServices.GetPartType(part).Value);
    }
}

ViewModelsLazy = mefContainer.GetExportsResolved<ViewModelBase, IViewModelMetadata>(unityContainer);

var regs = mefContainer.GetExportTypesWithMetadata<ViewModelBase, IViewModelMetadata>();
foreach (var reg in regs)
{
    unityContainer.RegisterType(typeof (ViewModelBase), reg.Key, reg.Value.Name);
}