C# 使用CancellationTokenSource取消多线程

 CancellationTokenSource cts ;
        /// <summary>
        /// 开启线程
        /// </summary>
        private void button1_Click(object sender, EventArgs e)
        {
            //重新实例化cts.Token就会不一样，不然再次点击的时候会报错，提示线程已经执行完毕
            cts = new CancellationTokenSource();
 
            Task task = new Task(() =>
            {
                Thread.Sleep(1500);
 
                try
                {
                    cts.Token.ThrowIfCancellationRequested();
                    MessageBox.Show("线程被执行");
                }
                catch (Exception ex)
                {
                    MessageBox.Show("线程被取消");
                }
 
            }, cts.Token);
            task.Start();
 
            //如果放到这里有可能线程还没有开始执行就被取消了
            //cts.Cancel(true);
        }
 
        /// <summary>
        /// 取消线程
        /// </summary>
        private void button2_Click(object sender, EventArgs e)
        {
            cts.Cancel();
        }

 CancellationTokenSource cts;
        /// <summary>
        /// 开启线程
        /// </summary>
        private void button1_Click(object sender, EventArgs e)
        {
            //重新实例化cts.Token就会不一样，不然再次点击的时候会报错，提示线程已经执行完毕
            cts = new CancellationTokenSource();
 
            for (int i = 0; i < 5; i++)
            {
                Task task = new Task((obj) =>
                {
                    Thread.Sleep(1500);
 
                    try
                    {
                        //cts.Token.ThrowIfCancellationRequested();
                        //检查状态,检查线程是否已经被取消，如果取消则自己跑出来一个线程
                        if (cts.Token.IsCancellationRequested)
                            throw new OperationCanceledException();
                        MessageBox.Show("线程" + obj + "被执行");
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("线程" + obj + "被取消");
                    }
 
                }, i, cts.Token);
                task.Start();
            }
            //如果放到这里有可能线程还没有开始执行就被取消了
            //cts.Cancel(true);
        }
 
        /// <summary>
        /// 取消线程
        /// </summary>
        private void button2_Click(object sender, EventArgs e)
        {
            cts.Cancel();
        }