system.reactive - Managing async service calls using Silverlight and Reactive Extensions -

so i'm reading on rx , having difficult time grokking it. have silverlight app needs make 6 calls specific service asynchronously. in old days, we'd handle making calls , querying userstate/token match response request since they're not guaranteed return in order called them. however, suspect rx handles in far more elegant manner. can't work. here's have far...

mycollection.add(new myobject(1)); mycollection.add(new myobject(2)); mycollection.add(new myobject(3)); mycollection.add(new myobject(4)); mycollection.add(new myobject(5)); mycollection.add(new myobject(6));  foreach (var myitem in mycollection) {     var myobservable = observable.fromeventpattern<myservicemethodcompletedeventargs>     (         f => myserviceclient.myservicemethodcompleted += f,         f => myserviceclient.myservicemethodcompleted -= f     ).take(1).observeon(synchronizationcontext.current);      myobservable.subscribe     (     s =>     {         if (s.eventargs.error == null)         {          myitem.myproperty = s.eventargs.result;         }     }     );      myserviceclient.myservicemethodasync(myitem); } 

i hope can see i'm trying achieve here...

what end of myobject's being set result of first call returns.

i'm sure it's silly haven't been able figure out yet.

thanks :)

consider trying observable.fromasyncpattern instead of observable.fromeventpattern. there trick using fromasyncpattern in silverlight (and phone) because begininvoke/endinvoke pair not exposed directly service proxy. however, if use interface service proxy rather service proxy itself, can access begin/end pattern:

imyservice svc = new myserviceclient(); var svcobservable = observable.fromasyncpattern<t, myserviceresultargs>                         (svc.beginmyservicemethod, svc.endmyservicemethod); 

now, can switch using foreach (an anti-pattern linq) making mycollection observable , selectmany between mycollection , service request follows:

var requestresult = myitem in mycollection.toobservable()                     result in svcobservable(myitem)                     select new {myitem, result};  requestresult.subscribe(result => result.myitem.myproperty = result.result); 

one additional word of caution: if use fromasyncpattern in silverlight way, result come on background thread. need take care teo delegate dispatcher.

if want see in action, check out last 20 minutes or of mix presentation @ http://channel9.msdn.com/events/mix/mix11/ext08.