DEV Community πŸ‘©β€πŸ’»πŸ‘¨β€πŸ’»

PeterMilovcik
PeterMilovcik

Posted on

One Good Reason Why You Should Not Use Async Void

Let's take a look at this little example.

class Program
{
    static void Main(string[] args)
    {
        try
        {
            AsyncVoidMethod();
            Console.WriteLine("No exception is thrown!");
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
    }

    private static async void AsyncVoidMethod()
    {
        throw new Exception("BOOM!");
    }
}
Enter fullscreen mode Exit fullscreen mode

What we have here is a method AsyncVoidMethod, which throws an exception and returns async void instead of async Task.

Since it's void, we cannot await it. What it also means that exception from an async call could not be saved anywhere because there is no Task object which could save it.

Output

No exception is thrown!

It's a dangerous problem: an exception is not handled!

Solution

I wouldn't like to describe a solution here, because John Thiriet already did a great job doing so, and you know, that duplication is evil, right?

Check this fantastic article for solution:
https://johnthiriet.com/removing-async-void/

Top comments (1)

Collapse
 
roubachof profile image
Jean-Marie Alfonsi

Hey man! Great subject!
I also created my own component to handle async void and process global error handler, statistic, ...

github.com/roubachof/Sharpnado.Tas...

We are hiring! Do you want to be our Senior Platform Engineer? Forem is hiring a Senior Platform Engineer

If you're interested in ops and site reliability and capable of dipping in to our Linux stack, we'd love your help shoring up our systems!