Thread.Sleep replacement in .NET for Windows Store

Question

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.

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, Sep 28 '12 at 13:46
Do you have Events or the `Monitor` class? You can use the `Wait` method with a timeout to simulate a sleep. — Tudor, Sep 28 '12 at 13:49
Yay for banishing `Thread.Sleep` to the dustbin of bad tech. — spender, Sep 28 '12 at 13:56

score 203 · Accepted Answer · answered Sep 28 '12 at 13:48

203

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.

answered Sep 28 '12 at 13:48

Jon Skeet

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Unfortunately, Task.Delay doesn't seem to be supported when targeting .NET 4.5 + store + WP7 in a portable class library.. I guess I'll have move this into the platform specific classes. – Max Sep 28 '12 at 14:13
1

@Max: No, because it didn't exist before .NET 4.5. IIRC, WP7 itself doesn't have any TPL support. (I could be wrong...) – Jon Skeet Sep 28 '12 at 14:14
4

You can tack on `.RunSynchronously()` if needed. – HappyNomad Mar 10 '13 at 01:44
You can also use Microsoft.Bcl.Async's TaskEx.Delay, you cab grab the package using NuGet. – Kanadaj Aug 07 '14 at 22:49
If it's awaitable, why didn't they call it `DelayAsync()`? – Jay Carlton Oct 19 '14 at 04:39
@Jay: It's felt that methods which are *clearly* about asynchrony are okay without the suffix, e.g. `Task.Run`. – Jon Skeet Oct 19 '14 at 06:26
@RAM: Well then it's not a Windows Store app to start with, so we're in a completely different context - I'd suggest that in that case you ask a new question with more details. – Jon Skeet Feb 16 '15 at 16:37
@JonSkeet, my platform is **C# .NET 3.5 WPF**. i found some ways but i don't know what is the best and short way. do you know any good answer in stackoverflow for it? I can write a new question but i like know your suggestions. do you suggest new question in stackoverflow? thanks... – Ramin Bateni Feb 16 '15 at 17:21
1

@RAM: Well `Thread.Sleep` *is* supported in .NET 3.5, so the question doesn't apply. No doubt you have *a* question, but it doesn't sound like it's the same as this one. Please read http://tinyurl.com/stack-hints then ask a new question. – Jon Skeet Feb 16 '15 at 17:22
2

@RAM: I'm not sure how I was meant to guess that from your comments. There are plenty of similar questions on SO already about WPF and animation. – Jon Skeet Feb 16 '15 at 18:03

score 46 · Answer 2 · answered Nov 03 '14 at 19:23

46

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

answered Nov 03 '14 at 19:23

Antony Thomas

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Johannes Egger · Answer 3 · 2017-07-17T19:06:16.093

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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));
}

edited Jul 17 '17 at 19:06

answered May 04 '13 at 12:29

Johannes Egger

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This is the best answer for portable coding. – zezba9000 Oct 22 '13 at 10:02
Use the "slim" version of this. – Brannon Jul 17 '17 at 15:39

score 11 · Answer 4 · edited Apr 26 '14 at 12:13

11

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!
}

edited Apr 26 '14 at 12:13

Asherah

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answered Oct 08 '12 at 20:41

Benny Code

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score -7 · Answer 5 · edited Sep 28 '12 at 13:55

-7

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 ...

edited Sep 28 '12 at 13:55

EaterOfCode

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answered Sep 28 '12 at 13:48

igrimpe

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I disagree. If the thread is a background thread and the sleep is short then it is more efficient to have it sleep for a few milliseconds than using a timer. – Jason Steele Jan 19 '13 at 19:42
1

and sometimes you're told to do it despite advising said authority figure of the consequences ;) – Jordan Jan 14 '14 at 21:28

Thread.Sleep replacement in .NET for Windows Store

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