Switch和Merge都存在于核心 Rx 库中，因此幻灯片中的代码实际上几乎逐字逐句地翻译成 Rx。
操作符在流的Switch流上工作——在 Rx 中这是一个类型IObservable<IObservable<T>>。
Switch 扁平化这个流流，只发送最新的流到它的输出，所以你最终得到一个IObservable<T>.
请参阅下面的 C# 示例。我在演讲中尽可能地重用了变量名，所以这应该很容易理解。
唯一（非常轻微）不同的是hold函数被替换为 Rx 等效项StartWith。
包括 nuget 包Rx-Main并将其作为控制台应用程序运行。代码订阅screen流并开始将帧从“Fuzz”通道渲染到控制台。它会提示您输入频道号。输入 1 或 2，您会看到输出切换到相应通道的帧。
// helper method to create channels
private static IObservable<string> CreateChannelStream(
string name, CompositeDisposable disposables)
{
// this hacks together a demo channel stream -
// a stream of "frames" for the channel
// for simplicity rather than using images, I use a string
// message for each frame
// how it works isn't important, just know you'll get a
// message event every second
var channel = Observable.Interval(TimeSpan.FromSeconds(1))
.Select(x => name + " Frame: " + x)
.Publish();
disposables.Add(channel.Connect());
return channel;
}
public static void Main()
{
// for cleaning up the hot channel streams
var disposable = new CompositeDisposable();
// some channels
var fuzz = CreateChannelStream("Fuzz", disposable);
var channel1 = CreateChannelStream("Channel1", disposable);
var channel2 = CreateChannelStream("Channel2", disposable);
// the button press event streams
var eButton1 = new Subject<Unit>();
var eButton2 = new Subject<Unit>();
// the button presses are projected to
// the respective channel streams
// note, you could obtain the channel via a function call here
// if you wanted to - to keep it close to the slides I'm not.
var eChan1 = eButton1.Select(_ => channel1);
var eChan2 = eButton2.Select(_ => channel2);
// create the selection "stream of streams"
// an IObservable<IObservable<string>> here
// that starts with "fuzz"
var sel = Observable.Merge(eChan1, eChan2).StartWith(fuzz);
// flatten and select the most recent stream with Switch
var screen = sel.Switch();
// subscribe to the screen and print the frames
// it will start with "fuzz"
disposable.Add(screen.Subscribe(Console.WriteLine));
bool quit = false;
// a little test loop
// entering 1 or 2 will switch
// to that channel
while(!quit)
{
var chan = Console.ReadLine();
switch (chan.ToUpper())
{
case "1":
// raise a button 1 event
eButton1.OnNext(Unit.Default);
break;
case "2":
// raise a button 2 event
eButton2.OnNext(Unit.Default);
break;
case "Q":
quit = true;
break;
}
}
disposable.Dispose();
}
