异步编程练习

通过本实验，熟悉和掌握任务的定义、创建和执行，以及任务的取消和状态获取。

1、创建一个WPF应用程序项目

2、将App.xaml中的Application.Resources节内容改为

3、修改MainWindow.xaml及代码隐藏类

MainWindow.xaml

MainWindow.cs主要内容

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp1
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        Button oldButton = new Button();
        public MainWindow()
        {
            InitializeComponent();
        }
        private void button_Click(object sender, RoutedEventArgs e)
        {
            Button btn = e.Source as Button;
            btn.Foreground = Brushes.Black;
            oldButton.Foreground = Brushes.Black;
            oldButton = btn;
            frame1.Source = new Uri(btn.Tag.ToString(), UriKind.Relative);
        }
    }
}

Page4.xml

Pag4.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp1.Examples
{
    /// <summary>
    /// Page4.xaml 的交互逻辑
    /// </summary>
    public partial class Page4 : Page
    {
        private System.Threading.CancellationTokenSource cts;
        private MyTasks t = new MyTasks();

        public Page4()
        {
            InitializeComponent();
            MyHelps.ChangeState(btnStart, true, btnStop, false);
        }

        private  void BtnStop_Click(object sender, RoutedEventArgs e)
        {
            cts.Cancel();
            MyHelps.ChangeState(btnStart,true,btnStop,false);
        }

        private async void BtnStart_Click(object sender, RoutedEventArgs e)
        {
            MyHelps.ChangeState(btnStart, false, btnStop, true);
            cts = new System.Threading.CancellationTokenSource();
            textBlock1.Text = "开始执行任务......";
            try
            {
                await Task.Run(() => t.Method1(), cts.Token);
                textBlock1.Text += "\n任务1执行完毕";
                var sum = await Task.Run(() => t.Method2(), cts.Token);
                textBlock1.Text += "\n任务2（计算1到1000的和）结果为："+sum;
                var a = await Task.Run(() => t.Method3(39, 8), cts.Token);
                textBlock1.Text += string.Format("\n任务3（求39除以8的商和余数）结果为：{0},{1}\n", a.Item1, a.Item2);
                while (true)
                {
                    textBlock1.Text += await Task.Run(() => t.Method1("a"),cts.Token);
                    textBlock1.Text += await Task.Run(() => t.Method1("b"),cts.Token);
                }


            }
            catch(OperationCanceledException)
            {
                textBlock1.Text += "\n任务被取消";
            }
           

        }
    }
}

运行结果

通过本实验，熟悉和掌握任务的定义、创建和执行，以及任务的取消和状态获取