All I have is a general example of the IObserver and IObservable interfaces. To use them within WCF, I would start with the Service Operation code – and make that class implement the IObservable interface (assuming your WCF service will be the publisher). It would need to implement Subscribe and Remove methods as shown below:

public class MagazineService : IMagazineService, IObservable
{

public IDisposable Subscribe(IObserver observer)
{
if (!observers.Contains(observer))
{
observers.Add(observer);
}

return new RemoveMe(observers, observer);
}

private class RemoveMe : IDisposable
{
private List> observers;
private IObserver observer;

public RemoveMe(List> observers, IObserver observer)
{
this.observers = observers;
this.observer = observer;
}

public void Dispose()
{
if (observer != null && observers.Contains(observer))
{
observers.Remove(observer);
}
}
}

}

I am having the same issue, I think it is missing to invoke the event… I’m struggling: How did you solve it?
Thanks