WeakEvent

from ByteAether

WeakEvent is a lightweight .NET library that implements the weak event pattern using weak references. It ensures that event subscribers don't prevent garbage collection, avoiding memory leaks.

Key Features

• Weak References: Subscribers are held weakly so they can be garbage-collected when no longer in use.
• Events With or Without Data: Choose between WeakEvent for notifications without data and WeakEvent<TEvent> for events that pass data.
• Automatic Cleanup: Dead subscribers are removed automatically during event publishing.
• Simple API: Intuitive methods for subscribing, unsubscribing, and publishing events.

Installation

Install via NuGet:

dotnet add package ByteAether.WeakEvent

Use the --version option to specify a preview version to install.

Usage

Using the WeakEvent

using ByteAether.WeakEvent; // Create an instance of the weak event without event data var myEvent = new WeakEvent(); // Create a subscriber and subscribe var subscriber = () => Console.WriteLine("Event received!"); myEvent.Subscribe(subscriber); // Raise the event await myEvent.PublishAsync();

Using the WeakEvent<TEvent>

using ByteAether.WeakEvent; // Create an instance of the weak event with event data var myEvent = new WeakEvent<MyEventData>(); // Create a subscriber and subscribe var subscriber = (MyEventData data) => Console.WriteLine("Received: " + data.Message); myEvent.Subscribe(subscriber); // Raise the event await myEvent.PublishAsync(new MyEventData("Hello, World!")); // Define your event data public record MyEventData(string Message);

API Overview

WeakEvent

• SubscriberCount
  Number of alive subscribers currently registered to the event.
• Subscribe(Action handler)
Subscribe(Func<Task> handler)
Subscribe(Func<CancellationToken, Task> handler)
  Subscribes the specified handler to the event. The handler will be invoked when the event is raised, provided that its target is still alive.
• Unsubscribe(Action handler)
Unsubscribe(Func<Task> handler)
Unsubscribe(Func<CancellationToken, Task> handler)
  Unsubscribes the specified handler from the event.
• PublishAsync(CancellationToken cancellationToken = default)
  Raises the event by invoking all live subscribers. Dead subscribers (whose targets have been garbage-collected) are removed.

WeakEvent<TEvent>

• SubscriberCount
  Number of alive subscribers currently registered to the event.
• Subscribe(Action<TEvent> handler)
Subscribe(Func<TEvent, Task> handler)
Subscribe(Func<TEvent, CancellationToken, Task> handler)
  Subscribes the specified handler to the event. The handler will be invoked when the event is raised, provided that its target is still alive.
• Unsubscribe(Action<TEvent> handler)
Unsubscribe(Func<TEvent, Task> handler)
Unsubscribe(Func<TEvent, CancellationToken, Task> handler)
  Unsubscribes the specified handler from the event.
• PublishAsync(TEvent eventData, CancellationToken cancellationToken = default)
  Raises the event by invoking all live subscribers with the provided event data. Dead subscribers (whose targets have been garbage-collected) are removed.