Question

以下是示例代码：

var task = Task.Factory.StartNew(() => { throw new Exception(); });
task.ContinueWith(t => Console.WriteLine("Exception"), TaskContinuationOptions.OnlyOnFaulted);
task.ContinueWith(t => Console.WriteLine("Success"), TaskContinuationOptions.NotOnFaulted)
    .ContinueWith(t => Console.WriteLine("Should not be executed. Task status = " + t.Status, TaskContinuationOptions.NotOnCanceled));
Console.ReadLine();

输出是（顺序无关紧要）：

异常

不应该执行。任务状态=已取消

为什么第二个ContinueWith被执行以及如何防止它？

Answer 1

您上次拨打ContinueWith时的括号错误：

.ContinueWith(t =>
    Console.WriteLine(
        "Should not be executed. Task status = " + t.Status,
        TaskContinuationOptions.NotOnCanceled));

TaskContinuationOptions.NotOnCanceled作为参数传递给WriteLine。

修正：

.ContinueWith(t =>
    Console.WriteLine(
        "Should not be executed. Task status = " + t.Status),
    TaskContinuationOptions.NotOnCanceled);

Answer 2

因为拼写错误， Ctrl + Shift + F1 它。

// ContinueWith([NotNull] Action<Task> continuationAction)
// WriteLine([NotNull] string format, object arg0)
.ContinueWith(t => Console.WriteLine("Should not be executed. Task status = " + t.Status, TaskContinuationOptions.NotOnCanceled));

// ContinueWith([NotNull] Action<Task> continuationAction, TaskContinuationOptions continuationOptions)
// WriteLine(string value) 
.ContinueWith(t => Console.WriteLine("Should not be executed. Task status = " + t.Status), TaskContinuationOptions.NotOnCanceled);

如何不继续取消任务？

2 个答案: