CODEWITHSUNDEEP
c#system.reactive
Benjol
Benjol

Reputation: 66531

Publish().RefCount() not working?

I have a mildly 'expensive' calculation exposed through an IObservable property.

I want to protect it from being run multiple times if there are multiple subscribers, so I put a Publish().RefCount() behind it, but when I stick breakpoints in, I still see it getting called twice.

public IObservable<int> Property
{
    get { return _Source.Select(Expensive).Publish().RefCount(); }
}

Upvotes: 2

Views: 191

Answers (1)

Benjol
Benjol

Reputation: 66531

It's only the result of Publish().RefCount() which is 'protected', not your source - as it stands, if you have multiple calls to your property, you will get multiple independent 'protected' observables - which will each subscribe independently to your source.

You need a backing field, which you can ensure will only be defined once:

private IObservable<int> _Property;
public IObservable<int> { get { return _Property; } }

//elsewhere:
_Property = _Source.Select(Expensive).Publish().RefCount()

(or alternatively)

public IObservable<int> { get; private set; }

//elsewhere:
_Property = _Source.Select(Expensive).Publish().RefCount()

Upvotes: 10

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