可取消可报告进度的Task

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApp2
{
    public partial class MainWindow : Window
    {
        CancellationTokenSource Cts = new CancellationTokenSource();
        public MainWindow()
        {
            Person p = new Person();
            p.Do(Cts.Token, new Progress<int>((xpp)=>label.Content=xpp));
        }

        /// <summary>
        /// 按钮按下事件处理函数
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            Cts.Cancel();
        }
    }

    public class Person
    {
        public string name { get; set; }
        public string age { get; set; }
        public int length { get; set; }
        public void Do(CancellationToken token, IProgress<int> progress)
        {
            Action action = new Action(() =>
            {
                try
                {
                    for (int i = 0; i < 30; i++)
                    {
                        Thread.Sleep(1000);
                        //报告进度
                        progress.Report(i);
                        //如果用户执行CancellationTokenSource.Cancel()方法就抛出异常
                        //从而达到取消线程操作
                        token.ThrowIfCancellationRequested();
                    }
                }
                catch (Exception)
                {
                    Console.WriteLine("取消线程执行");
                }
            });

            Task task = new Task(action,token);
            task.Start();
        }
    }
}

这里有一点需要说明，那就是Progress实际上是跨线程修改控件，去system.Progress源码中找到Report的源码中调用了OnReport函数，如下图：

m_synchronizationContext变量是个SynchronizationContext类型，用于线程间通信。