具有多个视图的Caliburn事件聚合器

我试图第一次使用Caliburn构建这个项目(也是MEF结构，我没有完全理解)。

我需要使用导体和EventAggregator。导体，因为我有一个AppViewModel"显示"3个按钮，将用户移动到3个不同的视图(AppView内的UserControls)。

我需要EventAggregator，因为这3个视图中的一个有一个按钮里面必须加载第4个视图(这必须是一个窗口，我认为，而不是一个UserControl，因为它必须是全屏)。所以我认为，当用户点击这个按钮在3视图(AppView中的UserControl)一个消息可以发送到监听器(应该是AppViewModel)，这一个应该ActivateItem(第4 vm)。

我不知道为什么，但即使遵循Caliburn项目的例子，我的消息也没有到达AppViewModel。

这是我的bootstrapper:

public class AppBootstrapper : Bootstrapper<AppViewModel>
    {
        private CompositionContainer container;
        protected override void Configure()
        {
            container = new CompositionContainer(new AggregateCatalog(AssemblySource.Instance.Select(x =>
                new AssemblyCatalog(x)).OfType<ComposablePartCatalog>()));
            CompositionBatch batch = new CompositionBatch();
            batch.AddExportedValue<IWindowManager>(new WindowManager());
            batch.AddExportedValue<IEventAggregator>(new EventAggregator());
            batch.AddExportedValue(container);
            container.Compose(batch);
        }
        protected override object GetInstance(Type serviceType, string key)
        {
            string contract = string.IsNullOrEmpty(key) ? AttributedModelServices.GetContractName(serviceType) : key;
            var exports = container.GetExportedValues<object>(contract);
            if (exports.Any())
                return exports.First();
            throw new Exception(string.Format("Could not locate any instances of contract {0}.", contract));
        }
        protected override IEnumerable<object> GetAllInstances(Type serviceType)
        {
            return container.GetExportedValues<object>(AttributedModelServices.GetContractName(serviceType));
        }
        protected override void BuildUp(object instance)
        {
            container.SatisfyImportsOnce(instance);
        }
        protected override void OnStartup(object sender, StartupEventArgs e)
        {
            DisplayRootViewFor<AppViewModel>();
        }
    }

AppViewModel:

[Export (typeof(AppViewModel))]
    public class AppViewModel : Conductor<object>, IHandle<ChangeViewEvent>
    {
        [ImportingConstructor]
        public AppViewModel(IEventAggregator events)
        {
            events.Subscribe(this);
            ActivateItem(new MainViewModel());            
        }
        public void GoToPatientsManager()
        {
            ActivateItem(new PatientsManagerViewModel(new WindowManager(), new EventAggregator()));
        }
        public void GoToTestManager()
        {
            ActivateItem(new TestManagerViewModel(new WindowManager()));
        }
        public void GoToResultsManager()
        {
            ActivateItem(new MainViewModel());
        }
        public void Handle(ChangeViewEvent message)
        {
            switch (message.ViewName)
            {
                case "TestManager" :
                    GoToTestManager();
                    break;
            }
        }
    }

这个视图模型应该启动加载第4个vm的请求

 [Export(typeof(PatientsManagerViewModel))]
    public class PatientsManagerViewModel : Screen
    {
        private readonly IWindowManager _windowManager;
        private readonly IEventAggregator eventAggregator;
        [ImportingConstructor]
        public PatientsManagerViewModel(IWindowManager windowManager, IEventAggregator eventAggregator)
        {
            _windowManager = windowManager;
            this.eventAggregator = eventAggregator;
        }
        #region Methods
        public void ShowFakeMessage()
        {
            dynamic settings = new ExpandoObject();
            settings.Placement = PlacementMode.Center;
            settings.PlacementTarget = GetView(null);
            var res = _windowManager.ShowDialog(new DeletePersonViewModel(), null, settings);
            if (res)
            {
                // The result of the dialog men. In this true case we'll use Linq to delete the entry from the database
                // using the dbContext
            }
        }
        public void GoToTestManager()
        {
            eventAggregator.Publish(new ChangeViewEvent("TestManager"));
        }
        #endregion
    }

没有到达AppViewModel的Handle方法

这些是错误的视图模型的实例?我无法从这里继续前进…

编辑

可以是，问题是，我通过一个新的EventAggregator对象，每次我激活一个新的PatientsManagerViewModel?任何建议吗?

public void GoToPatientsManager()
{
    var patientManagerViewModel = IoC.Get<PatientsManagerViewModel>();
    ActivateItem(patientManagerViewModel);
}