如何实现非通用接口并使用通用进行调用

Question

Probably a bad title, but I am trying to abstract away the type "EventHub" from my generic Handler class.

I would like to inject a function instead into my subscribe method to decouple the two types. Unfortunately, the only way I can see doing this is if I make my IHandler a generic, but this causes other problems.

Is there a design pattern to decouple these two types? Commented out are lines that I would like in some way.

public interface IHandler
{
    //void Subscribe(Func<Action<T>, Guid> subscribe);
    void Subscribe(EventHub eventHub);
    void Unsubscribe(Action<Guid> action);
}

public abstract class Handler<T> : IHandler
{
    private Guid _subscriptionToken;

    public virtual void Subscribe(EventHub eventHub)
    {
        var action = new Action<T>(Handle);
        _subscriptionToken = eventHub.Subscribe(action);
    }

    /*public virtual void Subscribe(Func<Action<T>, Guid> subscribe)
    {
        var action = new Action<T>(Handle);
        _subscriptionToken = subscribe(action);
    }*/

    public virtual void Unsubscribe(Action<Guid> action)
    {
        action(_subscriptionToken);
    }

    public abstract void Handle(T eventType);
}

Thanks for the help!

Answer 1

internal interface IHandler
{
    void Subscribe(Func<Action<object>, Guid> subscribe);
    void Unsubscribe(Action<Guid> action);
}

public abstract class Handler<T> : IHandler
{
    private Guid _subscriptionToken;

    public virtual void Subscribe(Func<Action<object>, Guid> subscribe)
    {
        var action = new Action<T>(HandleNonAsync);
        _subscriptionToken = subscribe(Convert(action));
    }

    public virtual void Unsubscribe(Action<Guid> action)
    {
        action(_subscriptionToken);
    }

    public abstract Task HandleAsync(T eventType);

    private void HandleNonAsync(T eventType)
    {
        HandleAsync(eventType).GetAwaiter().GetResult();
    }

    private Action<object> Convert(Action<T> myActionT)
    {
        if (myActionT == null) return null;
        else return new Action<object>(o => myActionT((T)o));
    }
}