在 Xamarin.Forms 中使用 Thread.Sleep

问题描述

我要执行以下操作

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;
                    })),
            },
        }
    }
};

我包含了 System.Threading 和 System.Threading.Tasks，但我仍然得到

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

当前上下文中不存在名称线程".

本网站建议 Thread.Sleep 可以在 Xamarin.Forms 中使用.我在一个共享项目中使用了这个，而不是一个 PCL.

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

推荐答案

如果你想等

异步:await Task.Delay(10000);

同步:Task.Delay(10000).Wait();

但请尽量避免阻塞 UI 线程，以确保良好的用户体验并保持您的应用响应速度.

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

在 Xamarin.Forms 中使用 Thread.Sleep

有两个 Xamarin.Forms 模板:

There are two Xamarin.Forms templates:

• Xamarin.Forms 可移植类库

• Xamarin.Forms Portable Class Library

因为PCL子集机制，你没有机会获得Thread.Sleep.

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

2017 年更新:PCL 现在已弃用.如果您使用 .netstandard 2.0，您可以按照习惯使用 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 共享项目

Xamarin.Forms Shared Project

此模板包含不支持 Thread.Sleep 的不同平台.Windows UWP、Xamarin.Android 和 Xamarin.iOS 支持它，Windows Phone 8.1 和 Windows 8.1 不支持.如果您卸载/删除这 2 个项目，则解决方案会生成.(不要忘记在 App.cs 中使用 System.Threading;)

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)

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