vbkalz3weh
New Member
I have a standalone Application which is using WCF with wsDualHttpBinding.This standalone application will randomly send message to any client which has subcribe the service by using the callback behavior of wsDualHttpBinding.The application subcribe and callback behavior is worked successfully if we use a window application as a client.Then I want to create an ASP.Net application which use SignalR as server push and subcribe the service provided by the above standalone application. When any message come back from the application, we will use SignalR to push the message and display it in browser.However, when tried to create such ASP.Net application, whenever the message callback from the standalone Application, the ASP.Net application will be shutdown.The following is the code for the hub of SignalR \[code\] public class MessageSubcriberHub : Hub{ private static readonly Dictionary<string, MessageSubcriber> Subcribers = new Dictionary<string, MessageSubcriber>(); public bool Subcribe() { if (Subcribers.Keys.Contains(Context.ConnectionId)) { return true; } try { MessageSubcriber sub = new MessageSubcriber(); sub.ConnectionId = Context.ConnectionId; if (sub.Subcribe()) { sub.listener += (string message, DateTime time) => { try { var context = GlobalHost.ConnectionManager.GetHubContext<MessageSubcriberHub>(); context.Clients.Client(sub.ConntectionId).MessageReceived(message, time); } catch { if (Subcribers.Keys.Contains(sub.ConntectionId)) { Subcribers.Remove(sub.ConntectionId); } } }; Subcribers.Add(Context.ConnectionId, sub); return true; } else { return false; } } catch (Exception ex) { return false; } } public bool Unsubcribe() { if (Subcribers.Keys.Contains(Context.ConnectionId)) { try { Subcribers[Context.ConnectionId].Dispose(); Subcribers.Remove(Context.ConnectionId); return true; } catch (Exception ex) { return false; } } return true; } public override Task OnDisconnected() { //return Clients.All.leave(Context.ConnectionId, DateTime.Now.ToString()); return new Task(new Action(()=>{ if (Subcribers.Keys.Contains(Context.ConnectionId)) { try { Subcribers[Context.ConnectionId].Dispose(); Subcribers.Remove(Context.ConnectionId); } catch (Exception ex) { } } })); }\[/code\]And the following is the code for the callback client\[code\][CallbackBehavior(ConcurrencyMode = ConcurrencyMode.Reentrant)]public class MessageSubcriber : IMessagingServiceCallback, IDisposable{ public string ConnectionId; MessagingServiceClient client; public delegate void MessageReceivedListener(string message, DateTime time); public event MessageReceivedListener listener; public MessageSubcriber() { InstanceContext context = new InstanceContext(this); client = new MessagingServiceClient(context, "WSDualHttpBinding_IMessagingService"); } public bool Subcribe() { return client.Subscribe(); } public bool Unsubcribe() { return client.Unsubscribe(); } public virtual void MessageReceived(string message, DateTime time) { if (listener != null) { listener.Invoke(message, time); } } public void Dispose() { client.Close(); }}\[/code\]I have checked the event viewer after the ASP.net Application shutdown. The following is the message shown in event viewer\[quote\] An unhandled exception occurred and the process was terminated. Application ID: 6ccca6be Process ID: 6184 Exception: System.Runtime.FatalException Message: Object reference not set to an instance of an object. StackTrace: at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc) at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet) at System.ServiceModel.Dispatcher.ChannelHandler.DispatchAndReleasePump(RequestContext request, Boolean cleanThread, OperationContext currentOperationContext) at System.ServiceModel.Dispatcher.ChannelHandler.HandleRequest(RequestContext request, OperationContext currentOperationContext) at System.ServiceModel.Dispatcher.ChannelHandler.AsyncMessagePump(IAsyncResult result) at System.ServiceModel.Dispatcher.ChannelHandler.OnAsyncReceiveComplete(IAsyncResult result) at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously) at System.Runtime.InputQueue\[code\]1.AsyncQueueReader.Set(Item item) at System.Runtime.InputQueue\[/code\]1.Dispatch() at System.ServiceModel.Channels.ReliableDuplexSessionChannel.ProcessDuplexMessage(WsrmMessageInfo info) at System.ServiceModel.Channels.ClientReliableDuplexSessionChannel.ProcessMessage(WsrmMessageInfo info) at System.ServiceModel.Channels.ReliableDuplexSessionChannel.HandleReceiveComplete(IAsyncResult result) at System.ServiceModel.Channels.ReliableDuplexSessionChannel.OnReceiveCompletedStatic(IAsyncResult result) at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously, Exception exception) at System.ServiceModel.Channels.ReliableChannelBinder\[code\]1.InputAsyncResult\[/code\]1.OnInputComplete(IAsyncResult result) at System.ServiceModel.Channels.ReliableChannelBinder\[code\]1.InputAsyncResult\[/code\]1.OnInputCompleteStatic(IAsyncResult result) at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously) at System.Runtime.InputQueue\[code\]1.AsyncQueueReader.Set(Item item) at System.Runtime.InputQueue\[/code\]1.EnqueueAndDispatch(Item item, Boolean canDispatchOnThisThread) at System.Runtime.InputQueue\[code\]1.EnqueueAndDispatch(T item, Action dequeuedCallback, Boolean canDispatchOnThisThread) at System.ServiceModel.Security.SecuritySessionClientSettings\[/code\]1.ClientSecurityDuplexSessionChannel.CompleteReceive(IAsyncResult result) at System.ServiceModel.Security.SecuritySessionClientSettings\[code\]1.ClientSecurityDuplexSessionChannel.OnReceive(IAsyncResult result) at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously, Exception exception) at System.ServiceModel.Security.SecuritySessionClientSettings\[/code\]1.ClientSecuritySessionChannel.ReceiveAsyncResult.OnReceive(IAsyncResult result) at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously, Exception exception) at System.ServiceModel.Channels.ReliableChannelBinder\[code\]1.InputAsyncResult\[/code\]1.OnInputComplete(IAsyncResult result) at System.ServiceModel.Channels.ReliableChannelBinder\[code\]1.InputAsyncResult\[/code\]1.OnInputCompleteStatic(IAsyncResult result) at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously) at System.Runtime.InputQueue\[code\]1.AsyncQueueReader.Set(Item item) at System.Runtime.InputQueue\[/code\]1.Dispatch() at System.Runtime.InputQueue`1.OnDispatchCallback(Object state) at System.Runtime.IOThreadScheduler.ScheduledOverlapped.IOCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped) at System.Runtime.Fx.IOCompletionThunk.UnhandledExceptionFrame(UInt32 error, UInt32 bytesRead, NativeOverlapped* nativeOverlapped) at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP) InnerException: System.NullReferenceException Message: Object reference not set to an instance of an object. StackTrace: at System.Web.HttpApplication.ThreadContext.Enter(Boolean setImpersonationContext) at System.Web.HttpApplication.OnThreadEnterPrivate(Boolean setImpersonationContext) at System.Web.AspNetSynchronizationContext.CallCallbackPossiblyUnderLock(SendOrPostCallback callback, Object state) at System.Web.AspNetSynchronizationContext.CallCallback(SendOrPostCallback callback, Object state) at System.Web.AspNetSynchronizationContext.Post(SendOrPostCallback callback, Object state) at System.ServiceModel.Dispatcher.ThreadBehavior.BindCore(MessageRpc& rpc, Boolean startOperation) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)\[/quote\]Does anyone have any idea?