C# VS2015 从表单更改为通用应用程序：缺少程序集错误

Question

I am writing a little program to control LEGO Mindstorms car using monobrick C# library from Monobrick.dk . I have used the library in Windows Forms and it worked. As I heard Forms are outdated way to write Windows apps so I would like to switch to Windows Universal Platform. I made a little code similar to the working one but I get error:

The type or namespace name 'Thread' does not exist in the namespace 'System.Threading' (are you missing an assembly reference?) App1 \\App1\\MainPage.xaml.cs 37

It is strange cause in Forms "System.Threading.Thread" worked.

Here is the code. It is supposed to turn Motor A in half power for 3 secs. after pushing an on screen button.

    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Runtime.InteropServices.WindowsRuntime;
    using Windows.Foundation;
    using Windows.Foundation.Collections;
    using Windows.UI.Xaml;
    using Windows.UI.Xaml.Controls;
    using Windows.UI.Xaml.Controls.Primitives;
    using Windows.UI.Xaml.Data;
    using Windows.UI.Xaml.Input;
    using Windows.UI.Xaml.Media;
    using Windows.UI.Xaml.Navigation;
    using MonoBrick.EV3;

    namespace App1
    {
public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();

        }

    private void button_Click(object sender, RoutedEventArgs e)
    {
        var ev3 = new Brick<Sensor, Sensor, Sensor, Sensor>("wifi");
        ev3.Connection.Open();
        ev3.MotorA.On(50);
        System.Threading.Thread.Sleep(3000);
        ev3.MotorA.Off();
           }
        }
    }

What am I missing here? Isn't WUP a little overkill for beginner? Maybe I should stick to WPF?

Will be grateful for your advice.

Answer 1

The System.Threading.Thread has been removed from the Windows Runtime (which powers the Universal Windows Platform). Instead, Microsoft wants you to focus on asynchronous programming patterns instead of using the Thread class directly (see this page for the asynchronous programming pattern documentation).

As answered in this question you should use the Task.Delay method, so your code would become something along the following lines:

private async void button_Click(object sender, RoutedEventArgs e)
{
    // code before
    await Task.Delay(3000);
    // code after
}

This has the added benefit that you UI would not become unresponsive, as the Thread.Sleep method would freeze the UI thread if it was not executed in another thread or asynchronous call.

You also might want to read this article about asynchronous programming in C# and VB.NET .