Best way to observe changes to SQL table or query in c#

Question

I have the following repository method...

IEnumerable<Client> repo.GetActiveClients();

What is the best way to periodically call this method and observe changes to the resulting enumerable list?

I am aware that RX provides .ToObservable() , which simplifies responding to changes in collection through subscriptions, but from examples I've seen, I can't work out how best to handle the polling and periodic calling of the method which will change the contents on the collection in the first place?

Answer 1

Unless I'm missing something in your question, I think this is the best option:

IDisposable subscription =
    Observable
        .Interval(TimeSpan.FromSeconds(15.0))
        .Select(x => repo.GetActiveClients())
        .Subscribe(clients =>
        {
            /* do something with the `clients` */
        });

Simple.