YuKitsune/Yuki.EventAggregator

A lightweight event aggregator implementation for .NET Standard 2.1

About

Yuki.EventAggregator provides a lightweight, and easy to use Event Aggregator implementation for .NET Standard 2.1 projects.

Usage

The IEventAggregator is capable of publishing IEvents, and invoking their associated handler methods. Event handler methods are simply void, or async Task methods, with only one parameter, which must implement the IEvent interface. The default implementation of the IEventAggregator is the InProcessEventAggregator, which as the name suggests, aggregates events throughout the host process.

Subscribing to Events

private readonly IEventAggregator _eventAggregator;
public void Main()
{
    // Create the new Event Aggregator instance
    _eventAggregator = new InProcessEventAggregator();

    // This tells the Event Aggregator to invoke OnSomeEvent whenever SomeEvent is published
    _eventAggregator.Subscribe<SomeEvent>(OnSomeEvent);

    // This does the same as above, but for the async variation
    _eventAggregator.Subscribe<SomeEvent>(OnSomeEventAsync);
}

public void OnSomeEvent(SomeEvent someEvent)
{
    ...
}

public async Task OnSomeEventAsync(SomeEvent someEvent)
{
    ...
}

The IEventAggregator can also automatically subscribe and unsubscribe any methods with the EventHandlerAttribute to their respective events:

private readonly IEventAggregator _eventAggregator;
public void Main()
{
    // Create the new Event Aggregator instance
    _eventAggregator = new InProcessEventAggregator();
    _eventAggregator.SubscribeAllHandlers(this);
}

[EventHandler]
public void OnSomeEvent(SomeEvent someEvent)
{
    ...
}

[EventHandler]
public async Task OnSomeEventAsync(SomeEvent someEvent)
{
    ...
}

public void Dispose()
{
    _eventAggregator.UnsubscribeAllHandlers(this);
}

⚠ Important note: If you're using this method, then make sure that UnsubscribeAllHandlers is invoked when the object is no longer being used. Implementing the IDisposable interface should make this easier to work with.

Publishing Events

// This will publish a new instance of SomeEvent, any synchronous event handler which is subscribed to the SomeEvent event will be invoked with the SomeEvent as it's parameter
_eventAggregator.Publish(new SomeEvent("Dummy string"));

// This will do the same as above, but will run asynchronously, and only async event handlers will be invoked
await _eventAggregator.PublishAsync(new SomeEvent("Dummy string"));

Contributing

Contributions are what make the open source community such an amazing place to be learn, inspire, and create. Any contributions you make are greatly appreciated.

1. Fork the Project
2. Create your Feature Branch (feature/AmazingFeature)
3. Commit your Changes
4. Push to the Branch
5. Open a Pull Request