我正在努力与我的第一个简单的“hello world”RX应用程序。我正在使用VS2010 RC,以及最新的RX下载。第一步与反应式扩展蹒跚步骤
以下是简单的控制台应用程序;
class Program
{
static void Main(string[] args)
{
var channel = new MessageChannel()
.Where(m => m.process)
.Subscribe((MyMessage m) => Console.WriteLine(m.subject));
//channel.GenerateMsgs();
}
}
public class MyMessage
{
public string subject;
public bool process;
}
public class MessageChannel: IObservable<MyMessage>
{
List<IObserver<MyMessage>> observers = new List<IObserver<MyMessage>>();
public IDisposable Subscribe(IObserver<MyMessage> observer)
{
observers.Add(observer);
return observer as IDisposable;
}
public void GenerateMsgs()
{
foreach (IObserver<MyMessage> observer in observers)
{
observer.OnNext(new MyMessage() {subject = "Hello!", process = true});
}
}
}
我在Where子句中得到一个ArgumentNullException。这是堆栈;
System.ArgumentNullException was unhandled
Message=Value cannot be null.
Parameter name: disposable
Source=System.Reactive
ParamName=disposable
StackTrace:
at System.Collections.Generic.AnonymousObservable`1.Disposable.Set(IDisposable disposable)
at System.Collections.Generic.AnonymousObservable`1.<>c__DisplayClass1.<Subscribe>b__0()
at System.Threading.Scheduler.NowScheduler.Schedule(Action action)
at System.Collections.Generic.AnonymousObservable`1.Subscribe(IObserver`1 observer)
at ConsoleApplication1.Program.Main(String[] args) in C:\Users\Jason\documents\visual studio 2010\Projects\ConsoleApplication1\ConsoleApplication1\Program.cs:line 18
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
非常感谢弗兰克,那打在头上。只需要改变Subcribe类来使用IObserver而不是IObservable(我不抱怨!)。我使用了IObserverable提供的MSDN示例(http://msdn.microsoft.com/en-us/library/dd990377(VS.100).aspx) – 2010-02-13 19:33:33
您也可以使用'Disposable.Create(()=> Unsubscribe(观察者)) - 'System.Reactive.Disposables'命名空间有许多有用的IDisposable实现 – AlexFoxGill 2013-03-28 09:19:12