using System;

using System.Threading;

using System.Threading.Tasks;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.Configuration;

​

namespace BackgroundServiceExample

{

    public class Program

    {

        public static async Task Main(string[] args)

        {

            var host = Host.CreateDefaultBuilder(args)

                .ConfigureServices((hostContext, services) =>

                {

                    //services.AddHostedService<TimePrintingService>();

                    services.AddSingleton<TimePrintingService>();

                })

                .Build();

            //var cancellationToken = new CancellationTokenSource(TimeSpan.FromSeconds(2)).Token;

            var cancellationToken = CancellationToken.None;

            //var zeService = host.Services.GetRequiredService<TimePrintingService>();

            /* * /

            zeService.StartAsync(cancellationToken);

            zeService.StartAsync(cancellationToken);

            zeService.StartAsync(cancellationToken);

            /* */

            await host.RunAsync();

        }

    }

​

    public class TimePrintingService : BackgroundService

    {

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)

        {

            while (!stoppingToken.IsCancellationRequested)

            {

                PrintCurrentTime();

                await Task.Delay(1000, stoppingToken);

            }

        }

​

        public override async Task StartAsync(CancellationToken cancellationToken)

        {

            PrintCurrentTime();

            await base.StartAsync(cancellationToken);

        }

        public override async Task StopAsync(CancellationToken cancellationToken)

        {

            Console.WriteLine($"Application is shutting down: {DateTime.Now}, Thread ID: {Thread.CurrentThread.ManagedThreadId}");

            await base.StopAsync(cancellationToken);

        }

​

        private void PrintCurrentTime()

        {

            Console.WriteLine($"Current time: {DateTime.Now}, Thread ID: {Thread.CurrentThread.ManagedThreadId}");

        }

    }

​

}