Question

在我使用Caliburn.micro框架学习MVVM之后......我正在尝试通过EventAggregator传递两个viewModels这样的代码（带有“无意义”的代码，仅用于测试）：

MainWindowViewModel.cs

namespace TOP
{
[Export(typeof(MainWindowViewModel))]
public class MainWindowViewModel : Conductor<IScreen>.Collection.OneActive
{
    readonly IWindowManager windowManager;
    private readonly IEventAggregator events;
    private bool _Logged;

    [ImportingConstructor]
    public MainWindowViewModel(IWindowManager windowManager, IEventAggregator events)
    {
        DisplayName = "TOP";
        this.events = events;
        events.Subscribe(this);
        this.windowManager = windowManager;
        windowManager.ShowDialog(new LoginViewModel(events));

    }

    public bool Logged
    {
        get { return _Logged; }
        set
        {
            _Logged = value;
            if(_Logged== true) 
                InitiateApp();
        }
    }

    public void Handle(LoginEvent message)
    {
        Logged = message.Logged;
    }

    private void InitiateApp() {
        ActivateItem(new TwoWindowViewModel());
        }
    }
}

LoginViewModel.cs

namespace TOP{ 

 [Export(typeof(IScreen))]
    public class LoginViewModel : Screen
    {
        private readonly IEventAggregator _events;

        [ImportingConstructor]
        public LoginViewModel(IEventAggregator events)
        {

           DisplayName = "Login";
           _events = events;
           Login();
        }


       public void Login()
       {
           _events.Publish(new LoginEvent(true));
       }
    }
}

LoginEvent.cs

    namespace TOP
    {
        public class LoginEvent
        {
           public LoginEvent(bool logged) 
           {
               Logged = logged;
           }

         public bool Logged { get; private set; }
    }
}

为什么 MainWindowViewModel 的句柄方法没有从 LoginViewModel 中获取已发布的消息？

感谢您的回复。

Answer 1

您的MainWindowViewModel需要实施IHandle<LoginEvent>。您已经使用正确的签名定义了该方法，因此您只缺少实际告诉编译器您实现接口的部分：

public class MainWindowViewModel
    : Conductor<IScreen>.Collection.OneActive, IHandle<LoginEvent>

可以在the documentation找到更多信息。

Caliburn micro ViewModel没有从另一个ViewModel中获取消息

1 个答案: