How to correctly override System.Timers.Timer Elapsed Event

Question

I want to override the default Elapsed event for the System.Timers.Timer class to easily be able to remove all event listeners when desired. Using Jorge's answer from this question, I came up with the following

       class CustomTimer : System.Timers.Timer {

            List<ElapsedEventHandler> delegates = new List<ElapsedEventHandler>();

            private new event ElapsedEventHandler _elapsed;

            public new event ElapsedEventHandler Elapsed {
                add {
                    _elapsed += value;
                    delegates.Add(value);
                }
                remove {
                    _elapsed -= value;
                    delegates.Remove(value);
                }
            }

            public void RemoveAllEvents() {
                foreach (ElapsedEventHandler e in delegates) {
                    _elapsed -= e;
                }
                delegates.Clear();
            }
        }

When I run the service that this is executing in, I can trace through to see that the private Elapsed member is being assigned. However I'm not able to see the event handler actually execute. Did I set this up correctly?

Charles · Accepted Answer · 2020-01-09T21:00:26.030

1

This is how i did it :

public void AddElapsed(ElapsedEventHandler newHandler)
{
    base.Elapsed += newHandler;
    delegates.Add(newHandler);
}

Then only use AddElapsed() instead of Elapsed +=

Maybe add the following as well:

[Obsolete]
public new event ElapsedEventHandler Elapsed;

edited Jan 09 '20 at 21:00

answered Jan 09 '20 at 20:15

Charles

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Did you still have to define a public event and private backing? – pingOfDoom Jan 09 '20 at 20:31
@pingOfDoom i don't touch the event, just inherited from timer and added a new method. – Charles Jan 09 '20 at 20:39
You don't have to redefine the event in the derived class? – pingOfDoom Jan 09 '20 at 20:55
nope you don't have to. If you want you can i guess and throw a warning that the new method should be used. Or maybe add an `[Obsolete]` attribute to the elapsed event – Charles Jan 09 '20 at 20:58

How to correctly override System.Timers.Timer Elapsed Event

1 Answers1