How to hit the breakpoint at catch block when working with TPL
As I started understanding thru the TPL. I got stuck over in this code. I have 2 task. Task1 thows ArgumentOutOfRangeException and Task2 throws NullReferenceException.
Consider this below code:
static void Main(string[] args) {
// create the cancellation token source and the token
CancellationTokenSource tokenSource = new CancellationTokenSource();
CancellationToken token = tokenSource.Token;
// create a task that waits on the cancellation token
Task task1 = new Task(() => {
// wait forever or until the token is cancelled
token.WaitHandle.WaitOne(-1);
// throw an exception to acknowledge the cancellation
throw new OperationCanceledException(token);
}, token);
// create a task that throws an exceptiono
Task task2 = new Task(() => {
throw new NullReferen开发者_Go百科ceException();
});
// start the tasks
task1.Start(); task2.Start();
// cancel the token
tokenSource.Cancel();
// wait on the tasks and catch any exceptions
try {
Task.WaitAll(task1, task2);
} catch (AggregateException ex) {
// iterate through the inner exceptions using
// the handle method
ex.Handle((inner) => {
if (inner is OperationCanceledException) {
// ...handle task cancellation...
return true;
} else {
// this is an exception we don't know how
// to handle, so return false
return false;
}
});
}
// wait for input before exiting
Console.WriteLine("Main method complete. Press enter to finish.");
Console.ReadLine();
}
I have put the try catch block for Task.WaitAll(task1, task2). It should ideally hit the breakpoint in ex.handler statement inside Catch block. As I understand that whatever may be the result it should hit the catch block.
Same case is happening if I have task1.Result/task2.Result.
My Question is: In debug mode why isn't the breakpoint being hit at the catch block when I am intentionally throwing it from task as I want to examine the statements under catch block. It just puts yellow mark at saying "NullReferenceException unhandled by the user code".
Task task2 = new Task(() => {
throw new NullReferenceException();
});
How do I hit the break point at catch block???
Thanks for replying :)
As Arne Claassen explained in their comment, the debugger pauses execution at the point the original exception is thrown because the thread does not handle the exception. If you continue exceution (F5 or play button), the program should continue to the point where you are handling the exception in your continuation.
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