.net - Observable.Create from Boo 的类型问题

Question

我正在尝试使用 Boo 的 Reactive Extensions 并遇到类型问题。这是基本示例：

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)

此处的订阅给出了 System.InvalidCastException: 无法从源类型转换为目标类型。问题似乎与我如何创建可观察对象有关，但我一直在努力寻找类型问题的来源。

想法？

Answer 1

Observable.Create接受Func<IObserver,Action>，但您OnSubscribe接受IObservable.

试试这个：

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)