How not to continue a cancelled task?

Question

Here is a sample code:

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();  

The output is (the order does not matter):

Exception

Should not be executed. Task status = Canceled

Why was the second ContinueWith executed and how to prevent it?

Answer 1

The parentheses in your last call to ContinueWith are wrong:

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

TaskContinuationOptions.NotOnCanceled is being passed as an argument to WriteLine .

Fixed:

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

Answer 2

Because typo, Ctrl + Shift + F1 it.

// 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);