Simple Event Aggregator

EventAggregator.cs

public class EventAggregator
{
    private readonly Dictionary<string, IList<Action<object>>> _events;

    public EventAggregator()
    {
        _events = new Dictionary<string, IList<Action<object>>>();
    }

    public void Subscribe(string eventKey, Action<object> handler)
    {
        if (!_events.ContainsKey(eventKey))
        {
            _events[eventKey] = new List<Action<object>> {handler};
        }
        else
        {
            _events[eventKey].Add(handler);
        }
    }

    public void Unsubscribe(string eventKey, Action<object> handler)
    {
        if (!_events.ContainsKey(eventKey)) return;

        while (_events[eventKey].Contains(handler))
        {
            _events[eventKey].Remove(handler);
        }
    }

    public void Publish(string eventKey, object args)
    {
        if (!_events.ContainsKey(eventKey)) return;

        foreach (var action in _events[eventKey])
        {
            action?.Invoke(args);
        }
    }
}