尽管InvocationList包含预订方法C＃，但EventHandler并未被调用

Question

I am developing a MEF application. I am using a plugin as a publisher and another as a subscriber. For the current issue I guarantee that both plugin instances are active. On the subscriber I subscribe to the event and on the publisher I iterate over the invocation list and call the BeginInvoke to raise the event asynchronously as so:

Publisher:

public class BackchannelEventArgs : EventArgs {
    public string Intensity { get; }
    public BackchannelEventArgs(string intensity) {
        this.Intensity = intensity;
    }
}

public class Publisher {
    public event EventHandler<BackchannelEventArgs> BackchannelEvent = delegate { };

    private void BackchannelEventAux(string bcintensity) {
        Plugin.LogDebug("BACKCHANNEL EVENT, sending to " + BackchannelEvent.GetInvocationList().Length + " subscribers: " + bcintensity);

        var args = new BackchannelEventArgs(bcintensity);
        foreach (EventHandler<BackchannelEventArgs> receiver in BackchannelEvent.GetInvocationList()) {
            receiver.BeginInvoke(this, args, null, null);
        }
    }
}

Subscriber (relevant snippet, the Init is being called by a pluginsManager in which I can see the logs):

class Subscriber {

    public void Init(){
        LogInfo("Before subscribing");
        publisher.BackchannelEvent += HandleBackchannelEvent;
        LogInfo("After subscribing");
    }

    private void HandleBackchannelEvent(object sender, BackchannelEventArgs e) {
        LogDebug("Handle Backchannel!");
    }
}

Now, the Log you see on the event handler is not called at all. I have 4 other events that follow the same structure and somewhat this event in particular is not being called (I can see the logs on the other events). The other plugins follow the exact same structure.

Already tried:

• Call synchronously BackchannelEvent(this, args) but the results are the same;
• Subscribe this same event on the other plugins as well but the issue remains on this single event (and not on the others who follow the same structure).

I hope you can give me some help on this.

Thank you

Edit: The shown code is a snippet. The Init method is being called by the pluginsManager. I have put a log before the subscribing call and I can confirm that I am indeed subscribing.

Edit2: The number of elements in the InvocationList is in fact 2 (the empty delegate and the subscriber) so it checks out.

Answer 1

Okay. I don't know why but I figured out the solution so that other ones who stumble with the issue can find a solution. It was related with a extension I created for the Random class (which wasn't throwing a exception although... so it might be a bug on C#, I can't really explain). The Random extension is provided by an external NuGet package I created.

Version A (without using the Random Extension):

Body of the EventHandler:

LogDebug("Inside Handler");
double intensityValue2 = GetRandomNumber(Settings.MinimumIntensity, Settings.MaximumIntensity);
double frequency2 = GetRandomNumber(Settings.MinimumFrequency, Settings.MaximumFrequency);
int repetitions2 = GetRandomInt(Settings.MinimuMRepetitions, Settings.MaximumRepetitions);

Version B (using Random extension):

Body of EventHandler:

LogDebug("Inside Handler");
double intensityValue2 = random.GetRandomNumber(Settings.MinimumIntensity, Settings.MaximumIntensity);
double frequency2 = random.GetRandomNumber(Settings.MinimumFrequency, Settings.MaximumFrequency);
int repetitions2 = random.GetRandomNumber(Settings.MinimuMRepetitions, Settings.MaximumRepetitions);

Version A is the one that it is working. The Logs are guaranteed to appear. I don't know why it isn't letting me use extensions but it is solved for now. It would make sense if the Random extension threw an exception but it is not the case...

If any other person stumbles upon the issue I hope this helps you figure out the issue faster than me.

Thank you

Edit: typo