什么是F＃的标准类型的事件？

Question

我正在尝试从F＃订阅/取消订阅C＃-made（在RabbitMQ客户端库中）：

AsyncEventingBasicConsumer.cs

AsyncEventingBasicConsumer.cs

public event AsyncEventHandler<BasicDeliverEventArgs> Received;

AsyncEventHandler.cs

我设法通过以下方式订阅了该活动：

AsyncEventHandler.cs

话虽如此，我想知道为什么下面的代码无法编译：

public delegate Task AsyncEventHandler<in TEvent>(object sender, TEvent @event) where TEvent : EventArgs;

因为我得到以下错误：

let subscribeAsync (channel: IModel) exchange callback =
    let consumer = AsyncEventingBasicConsumer(channel)
    consumer.add_Received(AsyncEventHandler<BasicDeliverEventArgs>(fun sender args -> Task.CompletedTask))
    // ...

我检查了

let subscribeAsync (channel: IModel) exchange callback =
    let consumer = AsyncEventingBasicConsumer(channel)
    consumer.Received.AddHandler(AsyncEventHandler<BasicDeliverEventArgs>(fun sender args -> Task.CompletedTask))
    // ...

，但看不到任何有关F＃的标准事件类型的引用。

Answer 1

F＃将.NET事件公开为Program.fs(10, 14): [FS1091] The event 'Received' has a non-standard type. If this event is declared in another CLI language, you may need to access this event using the explicit add_Received and remove_Received methods for the event. If this event is declared in F#, make the type of the event an instantiation of either 'IDelegateEvent<_>' or 'IEvent<_,_>'. 或the official MS documentation类型的值，具体取决于事件声明和委托类型。仅对于具有某些基本公共结构的事件，才可以执行此操作-当F＃无法执行此操作时，它将把事件的基础IEvent和IDelegateEvent操作公开为可以直接调用的方法。