Я пытаюсь написать класс, который инкапсулирует вызовы WCF (клиент - Silverlight, если это важно). Все работает нормально, но я не уверен, как отловить сбой соединения, как будто сервер не отвечает. Может показаться, что кое-что происходит в результирующем коде ChannelFactory, но я не уверен. Также приветствуется общий обзор кода. :)
Нижняя строка, окружающая создание канала или делегат результата begin или async в try / catch, не перехватывает сбойное соединение. Я бы хотел, чтобы этот улов запускал событие ServiceCallError.
public class ServiceCaller : IDisposable
{
private IFeedService _channel;
public ServiceCaller()
{
var elements = new List<BindingElement>();
elements.Add(new BinaryMessageEncodingBindingElement());
elements.Add(new HttpTransportBindingElement());
var binding = new CustomBinding(elements);
var endpointAddress = new EndpointAddress(App.GetRootUrl() + "Feed.svc");
_channel = new ChannelFactory<IFeedService>(binding, endpointAddress).CreateChannel();
}
public void MakeCall(DateTime lastTime, Dictionary<string, string> context)
{
AsyncCallback asyncCallBack = delegate(IAsyncResult result)
{
var items = ((IFeedService)result.AsyncState).EndGet(result);
if (ItemsRetrieved != null)
ItemsRetrieved(this, new ServiceCallerEventArgs(items));
};
_channel.BeginGet(lastTime, context, asyncCallBack, _channel);
}
public event ItemsRetrievedEventHandler ItemsRetrieved;
public event ServiceCallErrorHandler ServiceCallError;
public delegate void ItemsRetrievedEventHandler(object sender, ServiceCallerEventArgs e);
public delegate void ServiceCallErrorHandler(object sender, ServiceCallErrorEventArgs e);
public void Dispose()
{
_channel.Close();
_channel.Dispose();
}
}
Вот трассировка стека для любопытных:
An AsyncCallback threw an exception.
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously, Exception exception)
at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.OnGetResponse(IAsyncResult result)
at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClassd.<InvokeGetResponseCallback>b__b(Object state2)
at System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)
Чтобы это произошло, я запускаю приложение в браузере, а затем убиваю процесс веб-сервера из Visual Studio. В тестовой среде я получаю то же самое, отключая сетевое соединение для клиентской системы.
Вот ToString () ПОЛНОГО исключения:
System.Exception: An AsyncCallback threw an exception. ---> System.Exception: An AsyncCallback threw an exception. ---> System.ServiceModel.CommunicationException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound.
at System.Net.Browser.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)
at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClass5.<EndGetResponse>b__4(Object sendState)
at System.Net.Browser.AsyncHelper.<>c__DisplayClass2.<BeginOnUI>b__0(Object sendState)
--- End of inner exception stack trace ---
at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state)
at System.Net.Browser.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.CompleteGetResponse(IAsyncResult result)
--- End of inner exception stack trace ---
at System.ServiceModel.Channels.Remoting.RealProxy.Invoke(Object[] args)
at proxy_2.EndGet(IAsyncResult )
at CoasterBuzz.Feed.Client.ServiceCaller.<MakeCall>b__0(IAsyncResult result)
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
--- End of inner exception stack trace ---
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously, Exception exception)
at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.CallComplete(Boolean completedSynchronously, Exception exception)
at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.FinishSend(IAsyncResult result, Boolean completedSynchronously)
at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.SendCallback(IAsyncResult result)
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
--- End of inner exception stack trace ---
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously, Exception exception)
at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.OnGetResponse(IAsyncResult result)
at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClassd.<InvokeGetResponseCallback>b__b(Object state2)
at System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)
Кстати, единственный способ уловить это вообще - использовать событие UnhandledException уровня приложения в клиенте SL.