Using Thread.Sleep in Xamarin.Forms

c# xamarin xamarin.ios xamarin.forms sleep

28,352

Solution 1

If you want to wait

asynchronously: await Task.Delay(10000);

synchronously: Task.Delay(10000).Wait();

But please try to avoid blocking the UI thread to ensure a good user experience and keep your app responsive.

Using Thread.Sleep in Xamarin.Forms

There are two Xamarin.Forms templates:

Xamarin.Forms Portable Class Library

Because of the PCL subset mechanism, you have no chance to get Thread.Sleep.

Update 2017: PCLs are deprecated, now. If you use .netstandard 2.0, you can use Thread.Sleep as you are used to it.
Xamarin.Forms Shared Project

This Template contains different platforms that do not support Thread.Sleep. Windows UWP, Xamarin.Android and Xamarin.iOS support it, Windows Phone 8.1, and Windows 8.1 not. If you unload/delete the 2 projects, the solution builds. (don't forget using System.Threading; in your App.cs)

Solution 2

You can try to use

await Task.Delay(milliseconds);

if you want to put a delay in your thread.

For blocking you can do

Task.Delay(TimeSpan.FromSeconds(5)).Wait();

28,352

Author by

testing

Updated on July 09, 2022

Comments

testing almost 2 years

I want to execute the following

MainPage = new ContentPage
{
    Content = new StackLayout
    {
        Children =
        {
            new Button
            {
                Text = "Thread.Sleep",
                Command = new Command(() =>
                {
                    Thread.Sleep(1000);
                    MainPage.Animate("", x => MainPage.BackgroundColor = Color.FromRgb(x, x, x));
                }),
            },
            new Button
            {
                Text = "Task.Run + Thread.Sleep",
                Command = new Command(async () =>
                {
                    await Task.Run(() => Thread.Sleep(1000));
                    MainPage.Animate("", x => MainPage.BackgroundColor = Color.FromRgb(x, x, x));
                })
            },
            new Button
            {
                Text = "Device.StartTimer",
                Command = new Command(() => Device.StartTimer(
                    TimeSpan.FromSeconds(1),
                    () =>
                    {
                        MainPage.Animate("", x => MainPage.BackgroundColor = Color.FromRgb(x, x, x));
                        return false;
                    })),
            },
        }
    }
};

I included System.Threading and System.Threading.Tasks, but I still get

The name 'Thread' does not exist in the current context.

This site suggests that Thread.Sleep can be used in Xamarin.Forms. I have this in a shared project, not a PCL.

testing about 8 years

You could do that, but that is different from the example I want to try. The thread should get blocked with the first button not delayed. Do you have an idea what I'm missing? A reference in the sub projects?
Rahul Tripathi about 8 years

@testing:- Updated my answer to block it. Please check
testing about 8 years

You are right that the UI thread should not get blocked. Here it is only for demonstration purposes.
testing about 8 years

Do you have an idea why Thread isn't recognized? On the linked page it seems that it somehow works.
Sven-Michael Stübe about 8 years

I think you don't have Thread.Sleep because of a different PCL profile of your Core library. The more supported platforms you select in the PCL, the less supported classes / functions you can use.
testing about 8 years

Any ideas where this can be changed?
Sven-Michael Stübe about 8 years

If you use a Shared Library instead of a Portable Class Library, it should work. But be aware, that some platforms simply don't support Thread.Sleep (e.g. WinPhone 8.1)
testing about 8 years

I tried it in a new Blank App (Xamarin.Forms Shared) and I get the same behavior. Strange ...
Sven-Michael Stübe about 8 years

This is because the Template contains different platforms that do not support Thread.Sleep. Windows UWP, Xamarin.Android and Xamarin.iOS support it, Windows Phone 8.1, and Windows 8.1 not. if you unload/delete the 2 projects, the solution builds. (don't forget using System.Threading; in your App.cs.
testing about 8 years

That is the solution. Please edit you answer and I'll give you the tick.
Sven-Michael Stübe about 8 years

I summarized it in the answer.