Question

有多种方法可以观察任务中抛出的异常。其中一个是带有OnlyOnFaulted的ContinueWith：

var task = Task.Factory.StartNew(() =>
{
    // Throws an exception 
    // (possibly from within another task spawned from within this task)
});

var failureTask = task.ContinueWith((t) =>
{
    // Flatten and loop (since there could have been multiple tasks)
    foreach (var ex in t.Exception.Flatten().InnerExceptions)
        Console.WriteLine(ex.Message);
}, TaskContinuationOptions.OnlyOnFaulted);

我的问题：一旦failureTask开始，是否会自动观察异常，或者只有在我触摸'ex.Message后才会观察到异常？

Answer 1

访问Exception媒体资源后，系统会将其视为观察。

另见AggregateException.Handle。您可以改为使用t.Exception.Handle：

t.Exception.Handle(exception =>
            {
            Console.WriteLine(exception);
            return true;
            }
    );

Answer 2

样本

Task.Factory.StartNew(testMethod).ContinueWith(p =>
            {
                if (p.Exception != null)
                    p.Exception.Handle(x =>
                        {
                            Console.WriteLine(x.Message);
                            return false;
                        });
            });

在ContinueWith中观察任务异常

2 个答案: