c# - IObservable<T>.ToTask<T> method returns Task awaiting activation -

why task await forever?:

var task = observable     .fromeventpattern<messageresponseeventargs>(communicator, "pushmessagerecieved")     .where(i => i.eventargs.getrequestfromreceivedmessage().name == requestname)     .select(i => i.eventargs)     .runasync(system.threading.cancellationtoken.none)     .totask();  task.wait(); 

i know "pushmessagerecieved" fired; can set break point on select lambda , hit it. task.wait() never moves.

better update: firstasync() looking for:

    public static task<messageresponseeventargs> handlepushmessagerecievedasync(this icommunicator communicator, requestname requestname)     {         if (communicator == null) return task.fromresult<messageresponseeventargs>(null);          var observable = getcommunicatorobservableforpushmessagereceived(communicator);         return observable             .where(i => i.getrequestfromreceivedmessage().name == requestname)             .select(i => i)             .firstasync()             .totask();     } 

where getcommunicatorobservableforpushmessagereceived() is:

    static iobservable<messageresponseeventargs> getcommunicatorobservableforpushmessagereceived(icommunicator communicator)     {         if (communicatorobservableforpushmessagereceived == null)         {             communicatorobservableforpushmessagereceived = observable                 .fromeventpattern<messageresponseeventargs>(communicator, "pushmessagerecieved")                 .where(i => !ispreviousmessage(i.eventargs.getrequestfromreceivedmessage().eventid))                 .select(i => i.eventargs);         }          return communicatorobservableforpushmessagereceived;     } 

update: horrific (but works):

public static task<messageresponseeventargs> handlepushmessagerecievedasync(this icommunicator communicator, requestname requestname) {     if (communicator == null) return task.fromresult<messageresponseeventargs>(null);      var completionsource = new taskcompletionsource<messageresponseeventargs>();      observable         .fromeventpattern<messageresponseeventargs>(communicator, "pushmessagerecieved")         .where(i => i.eventargs.getrequestfromreceivedmessage().name == requestname)         .select(i => i.eventargs)         .toevent().onnext += (args) =>         {             if (args.response.errors != null && args.response.errors.any())             {                 completionsource.trysetexception(args.response.errors.select(j => new exception(j.errormessage)));             }             else             {                 completionsource.trysetresult(args);             }         };      return completionsource.task; } 

both runasync , totask yield the last value in observable. no value produced until observable completes. observables created fromeventpattern not complete. need force them complete take or until.

i'll note runasync , totask redundant , there isn't need both.

in case, i'll assume interested in first value makes through filter:

var task = observable     .fromeventpattern<messageresponseeventargs>(communicator, "pushmessagerecieved")     .firstasync(i => i.eventargs.getrequestfromreceivedmessage().name == requestname)     .select(i => i.eventargs)     .totask();  task.wait();