WCF的ReactiveUI命令导致更新Observable属性时出现线程错误

Question

我正在尝试使用ReactiveUI命令进行WCF调用并使用ObservableAsPropertyHelper捕获结果字符串。下面我收到以下错误消息的代码 -

WCF调用的回报，但在访问ObservableForProperty错误“调用线程不能因为不同的线程拥有它访问这个对象” - 消息和/或当提高其PropertyChanged

让我知道是否有人需要其他细节/代码。

视图模型：UserService.Authenticate是

public class LoginViewModel : ReactiveObject, IRoutableViewModel 
{ 
    public LoginViewModel(IScreen hostScreen , MainViewModel appRootViewModel, IUserService userService) 
    { 
     HostScreen = hostScreen; 

     UserService = userService; 
     Application = appRootViewModel; 
     var canLogin = this.WhenAny(x => x.LoginName, x => x.Password, (l, p) => 
      !String.IsNullOrWhiteSpace(l.Value) && !String.IsNullOrWhiteSpace(p.Value)); 

     LoginCommand = new ReactiveCommand(canLogin); 

     var loggedIn = LoginCommand.RegisterAsync(_ => Observable.Start(() => 
      { 
       var request = new Request 
       { 
        UserIdentity = new User.Identity 
        { 
         Login = LoginName, 
         Password = new User.Password { Old = Password } 
        } 

       }; 
       var authenticationResult = UserService.Authenticate(request).Authenticated; 

       return authenticationResult ? "Login Succeeded...Continuing" 
        : "Login Failed...Please try again"; 


      })); 
     loggedIn.Subscribe(s => 
     { 
      if (s == "Login Succeeded...Continuing to Analytics") 
      { 
       HostScreen.Router.Navigate.Execute(Application); 
      } 

     }); 

      message = new ObservableAsPropertyHelper<string>(loggedIn, 
      s => 
      { 

       raisePropertyChanged("Message"); 

      }); 

视图代码后面到WCF端点代理电话：

public partial class LoginView : IViewFor<LoginViewModel> 
{ 
    public LoginView() 
    { 
     InitializeComponent(); 

     this.WhenAnyValue(x => x.ViewModel).BindTo(this, x => x.DataContext); 
     this.Bind(ViewModel, model => model.Password, x => x.password.Text); 
     this.Bind(ViewModel, model => model.LoginName, view => view.userName.Text); 
     this.OneWayBind(ViewModel, model => model.Message, x => x.message.Content); 
     this.OneWayBind(ViewModel, x => x.LoginCommand, x => x.login.Command); 
    } 

    public static readonly DependencyProperty ViewModelProperty = 
DependencyProperty.Register("ViewModel", typeof(LoginViewModel), typeof(LoginView), new PropertyMetadata(null)); 


    object IViewFor.ViewModel 
    { 
     get { return ViewModel; } 
     set { ViewModel = (LoginViewModel)value; } 
    } 

    public LoginViewModel ViewModel 
    { 
     get 
     { 
      return (LoginViewModel)GetValue(ViewModelProperty); 
     } 
     set 
     { 
      SetValue(ViewModelProperty, 
       value); 
     } 
    } 

} 

}

Answer 1

更新：通过告诉观察者回调在当前同步上下文上运行。

.ObserveOn（SynchronizationContext.Current）

所以下面是LoginCommand可观察代码来解决上述问题。最后一行是编辑。

var loggedIn = LoginCommand.RegisterAsync(_ => Observable.Start(() => 
      { 


       Session<NullT> init = new Session<NullT> 
       { 
        SqlKey = System.Configuration.ConfigurationManager.AppSettings["sharedKey"].ToString() 

       }; 

       var initResponse = UserService.Initialize(init); 
       var authenticationResult = false; 
       if (initResponse.SessionOk) 
       { 
        initResponse.UserIdentity = new User.Identity 
        { 
         Login = LoginName, 
         Password = new User.Password { Old = Password } 
        }; 


        authenticationResult = UserService.Authenticate(initResponse).Authenticated; 
        return authenticationResult ? "Login Succeeded" 
         : "Login Failed...Please try again"; 
       } 
       else return "Failed to Initialize."; 


      }).ObserveOn(SynchronizationContext.Current)); 

Answer 2

大部分代码是正确的（除了您设置的地方message，只需使用loggedIn.ToProperty），但我记得，WCF试图通过摆脱SynchronizationContexts“帮助你”，你需要禁用这个（我不知道如何做到这一点虽然）