Boo中Observable.Create的類型問題

Question

我正在嘗試使用Boo的Reactive Extensions，並且遇到類型問題。 這是基本示例：

def OnSubscribe(observer as IObservable[of string]) as callable:
    print "subscribing"

    def Dispose():
        print "disposing"

    return Dispose

observable = System.Linq.Observable.Create[of string](OnSubscribe)
observer = System.Linq.Observer.Create[of string]({x as string | print x})
observable.Subscribe(observer)

此處的訂閱給出System.InvalidCastException：無法從源類型轉換為目標類型。 問題似乎與如何創建可觀察對象有關，但是我一直在努力尋找類型問題的來源。

有想法嗎？

Answer 1

Observable.Create接受Func<IObserver,Action> ，但是您的OnSubscribe接受IObservable 。

嘗試這個：

def OnSubscribe(observer as IObserver[of string]) as callable():
    print "subscribing"

    observer.OnNext("first and only value")
    observer.OnCompleted()

    def Dispose():
        print "disposing"

    return Dispose

observable = System.Linq.Observable.Create[of string](OnSubscribe)
observer = System.Linq.Observer.Create[of string]({x as string | print x})
observable.Subscribe(observer)