c# - appending timeouts to asynchronous requests in WinRT -

i'm using piece of code append timeout request call i'm making ensure don't encounter slow internet connection - , handled appropriately.
when meet timeout condition error message i've been unable fix within extended function.

how go task in general?

code:

public static class soextensions {     public static task<t> withtimeout<t>(this task<t> task, timespan duration)     {         return task.factory.startnew(() =>         {             bool b = task.wait(duration);             if (b) return task.result;             return default(t);         });     } } 

usage:

var response = await httpwebrequest                      .create(request)                      .getresponseasync()                      .withtimeout(timespan.fromseconds(1)); 

i handle aggregateexception (and through webexception), still generates aggregateexception when timeout fails.

i recommend using cancellationtoken timeouts (new cancellationtokensource(mytimespan).token), can use within async methods (e.g., httpclient, pass token getasync method). takes fewer resources because http request canceled.

but if want "external" timeout, more natural approach this:

public static async task<t> withtimeout<t>(this task<t> task, timespan duration) {   var timeout = task.delay(duration);   var completetask = await task.whenany(task, timeout);   if (completetask == timeout)     return default(t);   else     return await task; } 

this prevent exceptions being wrapped aggregateexception. it's not efficient cancellationtoken approach, though, this:

var timeout = new cancellationtokensource(timespan.fromseconds(1)); var response = await new httpclient().getasync(uri, timeout.token); 

note cancellationtoken approach throw operationcanceledexception instead of returning default(t) if there timeout.