Question

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

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)

订阅此处提供System.InvalidCastException：无法从源类型转换为目标类型。问题似乎在于我是如何创建可观察的，但我一直在努力查看类型问题的来源。

想法？

Answer 1

Observable.Create需要Func<IObserver,Action>，但您的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)

从Boo输入Observable.Create的问题

1 个答案: