Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Identity.UI;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Index.txt.Data;
using Index.txt.Models;
using Microsoft.AspNetCore.Identity.UI.Services;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace Index.txt
{
    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<TodoModelDbContext>(options =>
                options.UseSqlite(
                    Configuration.GetConnectionString("DefaultConnection")));
                
            //services.AddDefaultIdentity<IdentityUser>()
            services.AddIdentity<IdentityUser, IdentityRole>()
                .AddDefaultUI(UIFramework.Bootstrap4)
                .AddEntityFrameworkStores<TodoModelDbContext>();

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
                .AddRazorPagesOptions(options =>
                {
                    options.AllowAreas = true;
                    options.Conventions.AuthorizeAreaFolder("Identity", "/Account/Manage");
                    options.Conventions.AuthorizeAreaPage("Identity", "/Account/Logout");
                });
            
            services.ConfigureApplicationCookie(options =>
            {
                options.LoginPath = $"/Identity/Account/Login";
                options.LogoutPath = $"/Identity/Account/Logout";
                options.AccessDeniedPath = $"/Identity/Account/AccessDenied";
            });
            
            services.AddAuthentication().AddMicrosoftAccount(microsoftOptions =>
                {
                    microsoftOptions.ClientId = Configuration["Authentication:Microsoft:ClientId"];
                    microsoftOptions.ClientSecret = Configuration["Authentication:Microsoft:ClientSecret"];
                });
            
            services.AddSingleton<IEmailSender, EmailSender>();
        }

        // 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");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

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

            app.UseAuthentication();

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