How to convert an IEnumerable> to IObservabl

问题:

Is there a built in way to convert an IEnumerable<Task<T>> to an IObservable<T>. Order doesn't matter, just that I get things, though preferably as they're completed.

If it doesn't exist yet, what might be a good way to accomplish it?

回答1:

I believe this will work

tasks.Select(t => Observable.FromAsync(() => t))
     .Merge();

Each task will send its results to the observable sequence in whatever order they complete. You can subscribe to the sequence and do whatever you want with the results that way.

回答2:

You could do it this way:

var query = tasks.ToObservable().SelectMany(task => task.ToObservable());

Or, alternatively, like this:

var query =
    from t in tasks.ToObservable()
    from i in t.ToObservable()
    select i;

回答3:

I believe what you're looking for may be Observable.Start()

You can then append .Subscribe(callbackMethod) to the end and specify a callback if needed.

回答4:

As of Rx 2.0, there's a slightly easier way:

var query = tasks.ToObservable().Merge();