Task with built in exception handling?

Question

When using Tasks you have to take special care in handling exceptions, here is an example :

class Program
{
    static void Main(string[] args)
    {
        Task<int> task = new Task<int>(Test);
        task.ContinueWith(ExceptionHandler, TaskContinuationOptions.OnlyOnFaulted);
        task.Start();
        Console.ReadLine();
    }

    static int Test()
    {
        throw new Exception();
    }

    static void ExceptionHandler(Task<int> task)
    {
        var exception = task.Exception;
        Console.WriteLine(exception);
    }
}

From here

My question is if there is any way to make a custom Task that will handle(log to service) all exceptions without manually stating it by the developer? Some kind of help heritage.

You can derive from [`Task`](https://msdn.microsoft.com/en-us/library/system.threading.tasks.task(v=vs.110).aspx). Maybe make a custom task class that calls `base.ContinueWith(ExceptionHandler, TaskContinuationOptions.OnlyOnFaulted);` before calling `base.Start()` in the body of the `Start()` method that you create. — Quantic, Apr 25 '16 at 15:12
I am not sure if I understand whole use case. But what you could try is bubbling exception up and log it at highest level. If exception is thrown then it most likely means that your application is in incorrect state anyway. — Karolis Kajenas, Apr 25 '16 at 15:17

Peter B · Accepted Answer · 2016-04-25T17:19:47.073

You could create MyLoggingTask as a subclass of Task, implementing the constructors that are relevant to you, or all of them to be on the safe side (I see 8 of them in .NET Framework 4.5), and override the Start() method.

Then either replace every Task usage with MyLoggingTask + a reference to the namespace of your subclass, or minimize the 'manual' aspect with using Task = Your.NameSpace.MyLoggingTask, creating a Task alias that is in fact your own class.

As an alternative, you could create an Extension Method public static StartWithLogging<T>(this Task<T> task) which takes care of the ContinueWith. Then replace every Start() call with StartWithLogging() + reference the namespace of your extension class.

I'm afraid there are no easier options, and some degree of 'manually stating' will always be needed.

Task with built in exception handling?

1 Answers1