// -----

// This code is discussed in more detail at this blog post:

// https://www.devleader.ca/2023/01/27/async-void-how-to-tame-the-asynchronous-nightmare/

// -----

// History:

// 2022-01-29

// - Updating NexusLabs.Framework nuget package to assist with the exception:

//   Unhandled exception. System.InvalidOperationException: An attempt was made to transition a task to a final state when it had already completed.

//   Version 0.34 has the fix. If for some reason your .NET Fiddle isn't set to use that, please ensure at least version 0.34.

using System;

using System.Threading;

using System.Threading.Tasks;

var invoker = new GenericEventHandlerInvoker();

invoker.Event += async (s, e) =>

{

    await Task.Run(() => Console.WriteLine("Printing 1 from a task."));

    throw new InvalidOperationException("expected 1!");

};

invoker.Event += async (s, e) =>

{

    await Task.Run(() => Console.WriteLine("Printing 2 from a task."));

    throw new InvalidOperationException("expected 2!");

};

​

Console.WriteLine("Starting...");

try

{

    await invoker.InvokeAsync(

        ordered: false,

        stopOnFirstError: true);

}

catch (Exception ex)

{

    Console.WriteLine("We caught the exception!");

    Console.WriteLine(ex);

}

​

Console.WriteLine("Done!");

​

class GenericEventHandlerInvoker

{

    public event EventHandler<EventArgs> Event;

​

    public async Task InvokeAsync(

        bool ordered,

        bool stopOnFirstError)

    {

        // here is the extension method syntax we can see from NexusLabs.Framework

        await Event

            .InvokeAsync(

                this,

                EventArgs.Empty,

                ordered,

                stopOnFirstError)

            .ConfigureAwait(false);

    }

}