IObservable<> missing .Subscribe extension methods

Question

I\'m using RX extensions and WF4 to create a workflow which reacts to observable messages to progress the workflow. To do this, I bring in an object containing an IObservabl

Answer 1

You're missing this:

using System;

That's the namespace containing the ObservableExtensions static class with all the Subscribe extension methods.

Extension methods are "discovered" via using directives (as well as the namespace hierarchy of the code trying to use them).