ReactiveUI 调用线程不能访问这个对象，因为另一个线程拥有它 [英] ReactiveUI The calling thread cannot access this object because a different thread owns it

问题描述

如果我在后面的代码中使用绑定，单击更改 IsBusy 后会出现错误

If I use a binding in code behind, getting an error after click at change IsBusy

"The calling thread cannot access this object because a different thread owns it"

xml:

<Button x:Name="AsyncCommand"
                    Height="20"
                    Content="PushAsync"/>
<ProgressBar x:Name="IsBusy"
              Height="20"/>

CS:

this.Bind(ViewModel, x => x.IsBusy, x => x.IsBusy.IsIndeterminate);
this.BindCommand(ViewModel, x => x.AsyncCommand, x => x.AsyncCommand);

视图模型:

public class TestViewModel : ReactiveObject
    {
        public TestViewModel()
        {
            AsyncCommand = new ReactiveAsyncCommand();
            AsyncCommand
                .RegisterAsyncFunction(x => 
                 { IsBusy = true; Thread.Sleep(3000); return "Ok"; })
                .Subscribe(x => { IsBusy = false; });
        }

        private bool isBusy;

        public bool IsBusy
        {
            get { return isBusy; }
            set { this.RaiseAndSetIfChanged(x => x.IsBusy, ref isBusy, value); }
        }
        public ReactiveAsyncCommand AsyncCommand { get; protected set; }
    }

但是，如果我在 xaml 中进行绑定，则一切正常，如下所示:

But if I make a bind in xaml all works, like this:

CS:

DataContext = new TestViewModel();

xml:

<Button x:Name="AsyncCommand"
                    Height="20"
                    Content="PushAsync"
                    Command="{Binding AsyncCommand}"/>
<ProgressBar x:Name="IsBusy"
              Height="20"
              IsIndeterminate="{Binding IsBusy}"/>

为什么会这样?

推荐答案

试试这个:

public TestViewModel()
{
    AsyncCommand = new ReactiveAsyncCommand();
    AsyncCommand.Subscribe(_ => IsBusy = true);

    AsyncCommand
        .RegisterAsyncFunction(x => 
         { Thread.Sleep(3000); return "Ok"; })
        .Subscribe(x => { IsBusy = false; });
}

甚至更好:

ObservableAsPropertyHelper<bool> _IsBusy;
public bool IsBusy {
    get { return _IsBusy.Value; }
}

public TestViewModel()
{
    AsyncCommand = new ReactiveAsyncCommand();
    AsyncCommand
        .RegisterAsyncFunction(x => 
         { Thread.Sleep(3000); return "Ok"; })
        .Subscribe(x => { /* do a thing */ });

    AsyncCommand.ItemsInFlight
        .Select(x => x > 0 ? true : false)
        .ToProperty(this, x => x.IsBusy);
}

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