c# - 使主题同步不那么痛苦

Question

我想同步访问 BehaviorSubject<T> ，所以我想使用 Subject.Synchronize .但是，我对这个界面有几个痛点，想知道我是否缺少一种更令人愉快的做事方式。

首先，我不得不同时存储原始主题和同步主题。这是因为我有时会使用 Value属性(property) BehaviorSubject<T> .也是因为Synchronize的返回值不是一次性的，所以我必须需要存储原始主题的实例才能正确处理它。

其次，Synchronize的返回值是ISubject<TSource, TResult> , 这与 ISubject<T> 不兼容.

因此我最终得到这样的代码:

public class SomeClass
{
    private readonly BehaviorSubject<string> something;
    private readonly ISubject<string, string> synchronizedSomething;

    public SomeClass()
    {
        this.something = new BehaviorSubject<string>(null);

        // having to provide the string type here twice is annoying
        this.synchronizedSomething = Subject.Synchronize<string, string>(this.something);
    }

    // must remember to use synchronizedSomething here (I forgot and had to edit my question again, showing how easy it is to screw this up)
    public IObservable<string> Something => this.synchronizedSomething.AsObservable();

    // could be called from any thread
    public void SomeMethod()
    {
        // do some work

        // also must be careful to use synchronizedSomething here
        this.synchronizedSomething.OnNext("some calculated value");
    }

    public void Dispose()
    {
        // synchronizedSomething is not disposable, so we must dispose the original subject
        this.something.Dispose();
    }
}

是否有我缺少的更清洁/更好的方法？需要明确的是，我希望能够做的是这样的事情(伪代码):

public class SomeClass
{
    private readonly IBehaviorSubject<string> something;

    public SomeClass()
    {
        this.something = new BehaviorSubject<string>(null).Synchronized();
    }

    public IObservable<string> Something => this.something.AsObservable();

    // could be called from any thread
    public void SomeMethod()
    {
        // do some work

        this.something.OnNext("some calculated value");
    }

    public void Dispose()
    {
        this.something.Dispose();
    }
}

Answer 1

我从您发布的代码示例中得到了一些注释

1. IBehaviorSubject<string>不是 Rx.NET 中定义的类型。也许你的意思是ISubject<string> ？
2. 你通过了null作为 BehaviorSubject<T> 的默认值，通常当我看到这个时，用户实际上只是想要 ReplaySubject<string>(1) .这取决于您是否有 Where(x=>x!=null)或 Skip(1)作为代码库中某处的补偿行为。
3. 也许您想使用静态方法Subject.Synchronize(ISubject<T>)而不是扩展方法 .Synchronized() ？

这可能是上面示例代码的合适替代品。

public class SomeClass
{
    //Exposed as ISubject as I can't see usage of `Value` and `TryGetValue` are not present.
    private readonly ISubject<string> something;

    public SomeClass()
    {
        var source = new BehaviorSubject<string>(null);
        //Maybe this is actually what you want?
        //var source = new ReplaySubject<string>(1);
        this.something = Subject.Synchronize(source);
    }

    public IObservable<string> Something => this.something.AsObservable();

    // could be called from any thread
    public void SomeMethod()
    {
        // do some work

        this.something.OnNext("some calculated value");
    }
}