c# - 具有多个 ReactiveCommand IsExecuting 的单个 ObservableAsPropertyHelper

Question

来自样本here ，我正在尝试将 _SpinnerVisibility 更改为多个 reactivecommand 对象。所以下面的片段显示了我所做的..

public ReactiveCommand<object> ExecuteSearch { get; protected set; }

public ReactiveCommand<List<string>> OtherOperation { get; protected set; }

public AppViewModel(ReactiveCommand<object> testExecuteSearchCommand = null, IObservable<List<FlickrPhoto>> testSearchResults = null)
{

_SpinnerVisibility = OtherOperation.IsExecuting.Select(x=> x? Visibility.Visible : Visibility.Collapsed)                
                .ToProperty(this, x => x.SpinnerVisibility, Visibility.Hidden);
_SpinnerVisibility = ExecuteSearch.IsExecuting.Select(x=> x? Visibility.Visible : Visibility.Collapsed)                
                .ToProperty(this, x => x.SpinnerVisibility, Visibility.Hidden);
}

我在这里根据多个 react 命令设置可见性。但总是最后注册的命令会触发可见性。有没有办法根据 react 命令 ExecuteSearch, OtherOperation 更改可见性？

Answer 1

您需要将两个 IsExecuting 可观察对象合并为一个。

如果您的命令是互斥的(即它们不能同时执行)，这应该可行:

_SpinnerVisibility = new IReactiveCommand[] { ExecuteSearch, OtherOperation }
    .Select(cmd => cmd.IsExecuting)
    .Merge()
    .Select(x=> x? Visibility.Visible : Visibility.Collapsed)                
    .ToProperty(this, x => x.SpinnerVisibility, Visibility.Hidden);

如果可以，那么它会更像:

_SpinnerVisibility = new IReactiveCommand[] { ExecuteSearch, OtherOperation }
    .Select(cmd => cmd.IsExecuting)
    .CombineLatest()
    .Select(x => x.Any() ? Visibility.Collapsed : Visibility.Visible)                
    .ToProperty(this, x => x.SpinnerVisibility, Visibility.Hidden);

两者都适用于任意数量的命令。