How to cancel an observable sequence

Question

I have a very simple IObservable that acts as a pulse generator every 500ms:

var pulses = Observable.GenerateWithTime(0, i => true         


        

Answer 1

If you're using the GenerateWithTime (replaced now with Generate passing in a timespan func overload), you can replace the second parameter to evaulate the state of the cancellation token as follows:

var pulses = Observable.Generate(0,
    i => !ts.IsCancellationRequested,
    i => i + 1,
    i => i,
    i => TimeSpan.FromMilliseconds(500));

Alternatively, if your event which causes the cancellation token to be set can be converted to an observable itself, you could use something like the following:

pulses.TakeUntil(CancelRequested);

I posted a more detailed explanation at http://www.thinqlinq.com/Post.aspx/Title/Cancelling-a-Reactive-Extensions-Observable as well.