Question

Hi I have the following code:

    try
    {
        var t1 = Task.Factory.StartNew(() =>
        {
            Count(5, 10);
        });
        //t1.Wait(); //This line if uncommented causes the exception to be handled below....
        Console.WriteLine("done");
    }
    catch (AggregateException ex)
    {
        Console.WriteLine(ex);
    }

    private void Count(int start, int end)
    {
        for (var i = start; i <= end; i++)
        {
            Console.WriteLine(i);
            if (i == 7) throw new InvalidOperationException("Something bad happened");
            Thread.Sleep(1000);
        }
    }

If I dont want to wait on my task, but still want to handle exceptions, how can I achieve this?

Answer 1

Create a continuation that handles errors when the task fails:

var t1 = Task.Factory.StartNew(() =>
    {
        Count(5, 10);
    });
t1.ContinueWith(
    (task) =>
    {
        var error = task.Exception;
        // handle error
    }, TaskContinuationOptions.OnlyOnFaulted);

OnlyOnFaulted specifies that the continuation will run on a threadpool thread if the task fails. If the task completes successfully, then it won’t execute.