c# - System.Threading.Task does not contain definition -

i cant have .delay definition on system.threading.task.

 public async task<string> waitasynchronouslyasync()  {               await task.delay(10000);      return "finished";  } 

you using .net 4. then, there no task.delay. however, there library microsoft called microsoft.bcl.async, , provides alternative: taskex.delay.

it used this:

public async task<string> waitasynchronouslyasync() {              await taskex.delay(10000);     return "finished"; } 

your other options either update .net 4.5, or implement yourself:

public static task delay(double milliseconds) {     var tcs = new taskcompletionsource<bool>();     system.timers.timer timer = new system.timers.timer();     timer.elapsed += (o, e) => tcs.trysetresult(true);     timer.interval = milliseconds;     timer.autoreset = false;     timer.start();     return tcs.task; } 

(taken servy's answer here).