CODEWITHSUNDEEP
.netc#-4.0system.reactive
kshahar
kshahar

Reputation: 10513

Using the latest value from IObservable

I've got three IObservable of types Foo, Bar and Baz. In addition, there is a method defined as:

void DoWork(Foo foo);

The IObservable are defined elsewhere as Subject and OnNext is called from time to time.

Whenever new data is available (defined by some Where queries), I want to call the DoWork method with the latest Foo value. If no Foo values were generated the method should not be called.

What is the easiest way to do that?

To be more specific, see the following example. I'd like to call DoWork when bar or baz change, with the latest foo (f.id == 1):

void Wire(IObservable<Foo> foo, IObservable<Bar> bar, IObservable<Baz> baz)
{
    foo.Where(f => f.Id == 1)
        .Subscribe(f => DoWork(f));
}

Upvotes: 2

Views: 170

Answers (2)

Enigmativity
Enigmativity

Reputation: 117027

This works for me:

var ubar = bar.Select(x => Unit.Default);
var ubaz = baz.Select(x => Unit.Default);

ubar.Merge(ubaz)
    .CombineLatest(foo.Where(f => f.Id == 1), (u, f) => f)
    .Subscribe(f => DoWork(f));

Upvotes: 1

casperOne
casperOne

Reputation: 74530

You can use the Do extension method on the Observable class to do this:

IObservable<Foo> filteredList = foos.Where(...);

// Invoke DoWork on each instance of Foo.
filteredList.Do(DoWork);

Upvotes: 0

Related Questions