using System;

using System.Collections.Generic;

using System.Reactive.Disposables;

using System.Reactive.Linq;

using System.Threading.Tasks;

using Microsoft.Reactive.Testing;

​

public class Program

{

    protected static event EventHandler<EventArgs> CancelEvent;

​

    public static void Main()

    {

        var completed = false;

​

            var scheduler = new TestScheduler();

            var observable = Observable.Interval(TimeSpan.FromSeconds(1),

                                                 scheduler);

​

            var fromEvent = Observable.FromEventPattern<EventArgs>(p => CancelEvent += p,

                                                                   p => CancelEvent -= p,

                                                                   scheduler);

​

            var cancellable = observable.TakeUntil(fromEvent);

​

            var results = new List<long>();

​

            using (cancellable.Subscribe(results.Add,

                                         e => { throw new Exception("No exception is planned! {0}",

                                                                    e); },

                                         () => { completed = true; }))

            {                

                scheduler.AdvanceBy(TimeSpan.FromSeconds(3.5).Ticks);

​

                CancelEvent(null,

                            new EventArgs());

​

                scheduler.AdvanceBy(TimeSpan.FromSeconds(3).Ticks);

            }

            Console.WriteLine("Have I completed indeed? {0}", completed);

            Console.WriteLine("What has been registered before cancellation? {0}", string.Join(", ", results));

    }

}