c# - CancellationTokenSource.Cancel(false)

Question

    static void Main(string[] args)
    {
        CancellationTokenSource cts = new CancellationTokenSource();

        ThreadPool.QueueUserWorkItem(o => DoWork(cts.Token, 100));

        Thread.Sleep(500);

        try
        {
            cts.Token.Register(CancelCallback3);
            cts.Token.Register(CancelCallback2);
            cts.Token.Register(CancelCallback1);



            cts.Cancel(false);
        }
        catch (AggregateException ex)
        {
            foreach (Exception curEx in ex.Data)
            {
                Trace.WriteLine(curEx.ToString());    
            }

        }

        Console.ReadKey();
    }

    private static void CancelCallback1()
    {
        Trace.WriteLine("CancelCallback1 was called");
        throw new Exception("CancellCallback1 exception");
    }


    private static void CancelCallback2()
    {
        Trace.WriteLine("CancelCallback2 was called");
        throw new Exception("CancellCallback2 exception");
    }

    private static void CancelCallback3()
    {
        Trace.WriteLine("CancelCallback3 was called");
    }

    private static void DoWork(CancellationToken cancellationToken, int maxLength)
    {
        int i = 0;
        while (i < maxLength && !cancellationToken.IsCancellationRequested)
        {
            Trace.WriteLine(i++);
            Thread.Sleep(100);
        }
    }

输出是：

0
1
2
3
4
CancelCallback1 was called

根据http://msdn.microsoft.com/en-us/library/dd321703.aspx我希望得到 AggregateException，看起来 throwOnFirstException 参数在这里没有任何意义。我的代码有什么问题。

Answer 1

您需要使用 Task<> 类来获取 AggregateException。它是 ThreadPool.QueueUserWorkItem() 的替代品。

Answer 2

问题在于 Visual Studio 中缺乏强大的调试经验。我的 VS 调试器设置被设置为在第一次出现异常时停止。

仅供参考 CancellationTokenSource.Cancel(false) 与 ThreadPool 以及 Tasks 一起工作得很好。