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。

巴特西

可取消可报告进度的Task

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