using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

​

namespace WhenAllPattern

{

    public class Program

    {

        public static async Task Main(string[] args)

        {

            var pingTest = new PingTest();

            try{

                 await pingTest.Test();

            } catch (Exception ex) {

                Console.WriteLine(ex);

            }

        }

    }

​

    public class PingTest

    {

        public async Task Test()

        {

            var pingTasks = new List<IPing>()

            {

                new WorkingPing(),

                new BrokenPing(),

                new WorkingPing(),

                new BrokenPing()

            };

​

            await Task.WhenAll(pingTasks.Select(t => t.Ping()));

        }

    }

​

    public interface IPing

    {

        Task<bool> Ping();

    }

​

    public class WorkingPing : IPing

    {

        public async Task<bool> Ping()

        {

            await Task.Delay(1000);

            return true;

        }

    }

​

    public class BrokenPing : IPing

    {

        public Task<bool> Ping()

        {

            throw new Exception("Ping Broken");

        }

    }

}