是否有 Observable.Interval 的“热"等价物 [英] Is there a 'Hot' equivalent of Observable.Interval

问题描述

如果我执行以下操作:

var obs = 
    Observable
    .Interval(TimeSpan.FromSeconds(1))
    .Select(x => "A" + x.ToString());

obs
.Subscribe(x => Console.WriteLine("From first: " + x.ToString()));

Observable
.Timer(TimeSpan.FromSeconds(3))
.SelectMany(_ => obs)
.Subscribe(x => Console.WriteLine("From second: " + x.ToString()));

我会在 4 秒后得到这个:

I will get this after 4 seconds:

From first:  A0
From first:  A1
From first:  A2
From second: A0
From first:  A3

是否有一个与 Observable.Interval 等效的热"会产生这个:

Is there a 'Hot' equivalent to Observable.Interval that would produce this:

From first:  A0
From first:  A1
From first:  A2
From second: A3
From first:  A3

推荐答案

使用 Publish() 和 Connect() 会使冷的 observable 变热.

using Publish() and Connect() will turn your cold observable hot.

var published = Observable
   .Interval(...)
   .Select(...)
   .Publish();

var connectionSubscription = published.Connect();
var observerSubscription = published.Subscribe(...);

值得注意的是，一旦 Connect() 调用发生，序列就会很热.您可以在 Connect() 之前订阅，但请确保在某个阶段调用它，否则将不会观察到任何内容.Connect() 有一些替代方法，例如RefCount() 如此值得谷歌.另外值得注意的是，Publish() 返回一个 IConnectableObservable，它提供了 Connect() 调用.

Worth noting that the sequence is hot once the Connect() call happens. You can subscribe before the Connect() but make sure you call it at some stage or nothing will ever be observed. There are some alternatives to Connect() e.g. RefCount() so worth a google. Also worth noting that Publish() returns an IConnectableObservable which provides the Connect() call.

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