任务的取消

   //当其中一个线程异常之后 之后的线程都取消
多线程里面抛出的异常只会终结当前线程，不会影响其他线程

            try
            {
                List<Task> list2 = new List<Task>();
                CancellationTokenSource cts = new CancellationTokenSource();
                for (int i = 0; i < 50; i++)
                {
                    string name = i + "线程";
                    list2.Add(Task.Run(() =>
                    {
                        try
                        {
                            if (!cts.IsCancellationRequested)
                                Console.WriteLine(name + "开始");
                            Thread.Sleep(new Random().Next(50, 100));
                            if (name == "11线程" || name == "12线程")
                            {
                                cts.Cancel();
                                throw new Exception(name + "异常");
                            }
                            if (!cts.IsCancellationRequested)
                                Console.WriteLine(name + "结束");
                            else
                                Console.WriteLine(name + "被取消");
                        }
                        catch (Exception ex)
                        {
                            Console.WriteLine(ex.Message);
                            cts.Cancel();
                        }
                    }, cts.Token)); // cts.Token的作用：在cts.Cancel() 之后会抛出异常，即将cts.Cancel()之后的任务取消  cts.Cancel() 时还没有启动的任务就不启动了
                }
                Task.WaitAll(list2.ToArray());//1:捕捉到异常的线程
            }
            catch (AggregateException ex)//2 通过try catch AggregateException 遍历
            {
                foreach (var item in ex.InnerExceptions)
                {
                    Console.WriteLine(item.Message);
                }
            }
            catch (Exception ex)
            { }