从桌面到 Web - 二十几天学 ASP.NETCore 1

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

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>();
    }

/// <summary>
/// Builds the required services and an <see cref="IWebHost"/> which hosts a web application.
/// </summary>
public IWebHost Build()
{
.....
　　var hostingServices = BuildCommonServices(out var hostingStartupErrors);
.....
　　AddApplicationServices(applicationServices, hostingServiceProvider);

　　IServiceProvider GetProviderFromFactory(IServiceCollection collection)
　　{
　　var provider = collection.BuildServiceProvider();
　　var factory = provider.GetService<IServiceProviderFactory<IServiceCollection>>();

　　if (factory != null && !(factory is DefaultServiceProviderFactory))
　　{
　　　　using (provider)
　　　　{
　　　　return factory.CreateServiceProvider(factory.CreateBuilder(collection));
　　　　}
　　}

　　return provider;
　　}

}

private IServiceCollection BuildCommonServices(out AggregateException hostingStartupErrors)
{
...

　　var services = new ServiceCollection();
　　services.AddSingleton(_options);
　　services.AddSingleton<IWebHostEnvironment>(_hostingEnvironment);
　　services.AddSingleton<IHostEnvironment>(_hostingEnvironment);
　　#pragma warning disable CS0618 // Type or member is obsolete
　　services.AddSingleton<AspNetCore.Hosting.IHostingEnvironment>(_hostingEnvironment);
　　services.AddSingleton<Extensions.Hosting.IHostingEnvironment>(_hostingEnvironment);
　　#pragma warning restore CS0618 // Type or member is obsolete
　　services.AddSingleton(_context);

　　var builder = new ConfigurationBuilder()
　　.SetBasePath(_hostingEnvironment.ContentRootPath)
　　.AddConfiguration(_config, shouldDisposeConfiguration: true);

　　_configureAppConfigurationBuilder?.Invoke(_context, builder);

　　var configuration = builder.Build();
　　// register configuration as factory to make it dispose with the service provider
　　services.AddSingleton<IConfiguration>(_ => configuration);
　　_context.Configuration = configuration;

　　var listener = new DiagnosticListener("Microsoft.AspNetCore");
　　services.AddSingleton<DiagnosticListener>(listener);
　　services.AddSingleton<DiagnosticSource>(listener);

　　services.AddTransient<IApplicationBuilderFactory, ApplicationBuilderFactory>();
　　services.AddTransient<IHttpContextFactory, DefaultHttpContextFactory>();
　　services.AddScoped<IMiddlewareFactory, MiddlewareFactory>();
　　services.AddOptions();
　　services.AddLogging();

　　services.AddTransient<IServiceProviderFactory<IServiceCollection>, DefaultServiceProviderFactory>();

　　return services;
}

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));
            services.AddDefaultIdentity<IdentityUser>()
                .AddEntityFrameworkStores<ApplicationDbContext>();

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseDatabaseErrorPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseAuthentication();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }

services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));
services.AddDefaultIdentity<IdentityUser>()
                .AddEntityFrameworkStores<ApplicationDbContext>();