So I've this code:
//CancelationToken
CancellationTokenSource src = new CancellationTokenSource();
CancellationToken ct = src.Token;
ct.Register(() => Console.WriteLine("Abbruch des Tasks"));
//Task
Task t = new Task(() =>
{
System.Threading.Thread.Sleep(1000);
if (ct.IsCancellationRequested)
{
try
{
//Throw
ct.ThrowIfCancellationRequested();
}
catch (OperationCanceledException)
{
Console.WriteLine(
"ThrowIfCancellationRequested() liefert eben eine Exception");
}
}
}, ct);
//Run Task and Cancel
t.Start();
src.CancelAfter(350);
t.Wait();
// Get Information
Console.WriteLine("Canceled: {0} . Finished: {1} . Error: {2}",
t.IsCanceled, t.IsCompleted, t.IsFaulted);
So in this case I canceled my Task but my output in the end is: "Canceled: False . Finished: True . Error: False"
In my opinion it should be "Canceled:True . Finished:False". Why do I get this result? Because I try to catch the exception?
I've tried it without the try - catch block, but then my program stops because of the OperationCanceledException. Can somebody help me?
You're swallowing the exception, thus the task is flagged as finished as you actually handle the exception and it doesn't propagate outwards.
Instead, don't catch the exception inside the delegate, catch it outside:
void Main()
{
CancellationTokenSource src = new CancellationTokenSource();
CancellationToken ct = src.Token;
ct.Register(() => Console.WriteLine("Abbruch des Tasks"));
Task t = Task.Run(() =>
{
System.Threading.Thread.Sleep(1000);
ct.ThrowIfCancellationRequested();
}, ct);
src.Cancel();
try
{
t.Wait();
}
catch (AggregateException e)
{
// Don't actually use an empty catch clause, this is
// for the sake of demonstration.
}
Console.WriteLine("Canceled: {0} . Finished: {1} . Error: {2}",
t.IsCanceled, t.IsCompleted, t.IsFaulted);
}
この記事はインターネットから収集されたものであり、転載の際にはソースを示してください。
侵害の場合は、連絡してください[email protected]
コメントを追加