取消异步任务？

Question

我的代码没有正确取消任务，我仍然看到我的图表中的系列正在为循环中的下一个系列绘制foreach...不确定我在这里做错了什么，因为我想退出并取消所有异步此时的任务...有什么想法吗？    private void StartTest_Click(object sender, RoutedEventArgs e)    {        var cancellationTokenSource = new CancellationTokenSource();        if (_isRunning)        {            cancellationTokenSource.Cancel();        }        _isRunning = !_isRunning;        Start(cancellationTokenSource.Token);    }    private async void Start(CancellationToken cancellationToken)    {        foreach (var buttonSelected in selectedButtons)        {            // If cancellation requested            if (cancellationToken.IsCancellationRequested)                break;            // Retrieve series to reflect changes on            var seriesToChange = Model.Series.Where(x => x.Title == buttonSelected.Name).ToArray();            // Create timer            var timerForPlotting = new DispatcherTimer();            if (seriesToChange .Length == 1)            {                // Set the series to visible                seriesToChange [0].IsVisible = true;                timerForPlotting.Interval = TimeSpan.FromMilliseconds(50);                timerForPlotting.Tick += (object s, EventArgs a) => PlotSeriesPoints_Tick(s, a, seriesToChange [0]);            }            // Start            InitiateTimerWithButtonUIChange(timerForPlotting, buttonSelected, false);            // Set the task to only take a couple of seconds            await Task.Delay(2000);            // End            InitiateTimerWithButtonUIChange(timerForPlotting, buttonSelected, true);        }    }

Answer 1

尝试调用您用来创建传递给的令牌的Cancel()实际内容：CancellationTokenSourceStart

CancellationTokenSource cancellationTokenSource;

private void StartTest_Click(object sender, RoutedEventArgs e)

{

    if (cancellationTokenSource != null)

    {

        cancellationTokenSource.Cancel();

        cancellationTokenSource.Dispose();

    }

    cancellationTokenSource = new CancellationTokenSource();

    _isRunning = !_isRunning;

    Start(cancellationTokenSource.Token);

}