Thread.Sleep replacement in .NET for Windows Store

99
votes

Thread.Sleep doesn't seem to be supported in .NET for Windows Store apps.

For example, this

System.Threading.Thread.Sleep(1000);

will compile when targeting any .NET Framework (2.0, 3.5, 4.0, 4.5), but not when targeting .NET for Windows Store apps (or in a portable class library which targets both 4.5 and store).

System.Threading.Thread is still there, it just doesn't have the Sleep method.

I need to delay something for a few seconds in my app, is there a suitable replacement?

EDIT why the delay is needed: My app is a game and the delay is to make it look like the computer opponent is "thinking" about his next move. The method is already called asynchronously (main thread isn't blocked), I just want to slow the response time down.

5
c#.netwindows-storewindows-store-apps
Considering Windows Store apps are not supposed to be able to freeze the UI (everything is supposed to be async) it makes sense that it is not supported. – Sruly
Do you have Events or the Monitor class? You can use the Wait method with a timeout to simulate a sleep. – Tudor
is this for Apptivate.ms ? :3 – EaterOfCode
Yay for banishing Thread.Sleep to the dustbin of bad tech. – spender

5 Answers

203
votes

Windows Store apps embrace asynchrony - and an "asynchronous pause" is provided by Task.Delay. So within an asynchronous method, you'd write:

await Task.Delay(TimeSpan.FromSeconds(30));

... or whatever delay you want. The asynchronous method will continue 30 seconds later, but the thread will not be blocked, just as for all await expressions.

46
votes

Hate to state the obvious but in case anybody wanted a single line System.Threading.Tasks.Task.Delay(3000).Wait()

20
votes

I just had the same problem and found another interesting solution that I wanted to share with you. If you really want to block the thread I would do it like this (thanks @Brannon for the "slim" hint):

// `waitHandle.Set` is never called, so we wait always until the timeout occurs
using (var waitHandle = new ManualResetEventSlim(initialState: false))
{
    waitHandle.Wait(TimeSpan.FromSeconds(5));
}
11
votes

MainPage.xaml.cs

public MainPage()
{
  this.InitializeComponent();
  this.WaitForFiveSeconds();
}

private async void WaitForFiveSeconds()
{
  await System.Threading.Tasks.Task.Delay(TimeSpan.FromSeconds(5));
  // do something after 5 seconds!
}
-7
votes

There is almost NO reason (except for testing purposes) to EVER use Thread.Sleep().

IF (and only if) you have a very good reason to send a thread to sleep, you might want to check Task.Delay() , which you can await to "wait" for a specified time. Though it's never a good idea to have a thread sitting around and do nothing. Bad practise ...