Example for Worker Service + ASP.Net Web Server. Refer to https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/windows-service?view=aspnetcore-3.1&tabs=visual-studio

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.Logging;
using System.IO;
using Microsoft.Extensions.FileProviders;

namespace WorkerService2 {
    public class Program {
        public static void Main(string[] args) {
            CreateHostBuilder(args)
                .Build()
                .Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder => {
                    webBuilder.UseKestrel()
                        .UseUrls("http://127.0.0.1:80")
                        .ConfigureServices(services => {
                            services.AddSignalR();
                            services.AddRazorPages();
                        })
                        .Configure(app => {
                            app.UseRouting();
                            app.UseEndpoints(conf => {
                                conf.MapRazorPages();
                            });
                        });
                })
                .ConfigureServices((hostContext, services) => {
                    services.AddHostedService<Worker>();
                });
    }
}