using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

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

        Task example = Example();

        example.Wait();

        Console.WriteLine("Exiting Main()");

    }

    private static async Task Example()

    {

        Task[] tasks = new [] { DoLongThingAsyncEx1(), DoLongThingAsyncEx2() };

        Task allTasksCompleted = Task.WhenAll(tasks);

​

        try

        {

            await allTasksCompleted;

        }

        catch (Exception singleEx) 

        {

            Console.WriteLine("'await allTasksCompleted' threw exception of type " + singleEx.GetType().Name.ToString());

            Console.WriteLine("allTasksCompleted.Exception is type " + allTasksCompleted.Exception.GetType().Name);

            Console.WriteLine("allTasksCompleted.Exception.InnerException is type " + allTasksCompleted.Exception.InnerException.GetType().Name);

​

            List<AggregateException> exceptions = tasks.Where(t => t.Exception != null)

                                  .Select(t => t.Exception)

                                  .ToList();

            Console.WriteLine(exceptions.Count.ToString() + " exception(s) occurred across tasks[]:");

            foreach(AggregateException ex in exceptions) {

                Console.WriteLine("--> " + ex.GetType().Name + " [" + ex.InnerExceptions.Count.ToString() + " InnerException(s)]");

                foreach(var innerEx in ex.InnerExceptions) {

                    Console.WriteLine(" \\--> " + innerEx.GetType().Name);

                }

            }

        }

    }

​

    private static Task DoLongThingAsyncEx1()

    {

        return Task.Run(() => { throw new InvalidTimeZoneException(); });

    }

​

    private static Task DoLongThingAsyncEx2()

    {

        return Task.Run(() => { throw new InvalidOperationException(); });

    }

}