c# - Async operation completes, but result is not send to browser -

i want implement webchat.

the backend dual wcf channel. dual channel works in console or winforms, , works on web. can @ least send , receive messages.

as base used this blog post so, async operation completes.

when debug result, see messages ready send browser.

[asynctimeout(chatserver.maxwaitseconds * 1020)] // timeout bit longer internal wait public void indexasync() {   chatsession chatsession = this.getchatsession();   if (chatsession != null)   {     this.asyncmanager.outstandingoperations.increment();     try     {       chatsession.checkformessagesasync(msgs =>       {         this.asyncmanager.parameters["response"] = new chatresponse { messages = msgs };         this.asyncmanager.outstandingoperations.decrement();       });     }     catch (exception ex)     {       logger.errorexception("failed check messages.", ex);     }   } }  public actionresult indexcompleted(chatresponse response) {   try   {     if (response != null)     {       logger.debug("async request completed. number of messages: {0}", response.messages.count);     }     jsonresult retval = this.json(response);     logger.debug("rendered response: {0}", retval.);     return retval;   }   catch (exception ex)   {     logger.errorexception("failed rendering response.", ex);     return this.json(null);   } } 

but nothing sent.

checking fiddler, see request never response.

[sessionstate(sessionstatebehavior.readonly)]   public class chatcontroller : asynccontroller 

i had set sessionstatebehaviour readonly, otherwise async operation block whole page.

edit: here checkformessagesasync:

public void checkformessagesasync(action<list<chatmessage>> onmessages) {   if (onmessages == null)     throw new argumentnullexception("onmessages");    task task = task.factory.startnew(state =>          {     list<chatmessage> msgs = new list<chatmessage>();     manualreseteventslim wait = new manualreseteventslim(false);     action<list<chatmessage>> callback = state action<list<chatmessage>>;     if (callback != null)     {       idisposable subscriber = m_messages.subscribe(chatmessage =>       {         msgs.add(chatmessage);         wait.set();       });       bool success;       using (subscriber)       {         // wait max seconds new msg         success = wait.wait(timespan.fromseconds(chatserver.maxwaitseconds));                     }       if (success) this.safecallonmessages(callback, msgs);       else this.safecallonmessages(callback, null);     }           }, onmessages); } private void safecallonmessages(action<list<chatmessage>> onmessages, list<chatmessage> messages) {   if (onmessages != null)   {     if (messages == null)       messages = new list<chatmessage>();     try     {       onmessages(messages);     }     catch (exception ex)     {       this.logger.errorexception("failed call onmessages callback.", ex);     }   } } 

it`s same idea in refered blog post

edit2: btw, when nothing received, wait timeout comes play, reponse returns. seems crash somewhere. idea how log this?

i changed jquery request (see original blog post) post get. fixes it.