使用IDisposable取消订阅事件

public class EventPublisher
{
    public event EventHandler<string> OnEvent;

    public void Publish(string message)
    {
        OnEvent?.Invoke(this, message);
    }
}

public class EventSubscriber : IDisposable
{
    private EventPublisher _publisher;
    private EventHandler<string> _handler;

    public EventSubscriber(EventPublisher publisher)
    {
        _publisher = publisher;
        _handler = (sender, message) => Console.WriteLine($"Received message: {message}");
        _publisher.OnEvent += _handler;
    }

    public void Dispose()
    {
        _publisher.OnEvent -= _handler;
    }
}

public static void Main(string[] args)
{
    var publisher = new EventPublisher();
    using (var subscriber = new EventSubscriber(publisher))
    {
        publisher.Publish("Hello, world!");
    }

    publisher.Publish("This message should not be received.");
}