Startup.cs

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

namespace surveyjs_aspnet_mvc
{
    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.AddMvc();

            // Adds a default in-memory implementation of IDistributedCache.
            services.AddDistributedMemoryCache();

            services.AddSession(options => {
                // Set a short timeout for easy testing.
                options.IdleTimeout = TimeSpan.FromSeconds(300);
                options.Cookie.HttpOnly = true;
            });

        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment()) {
                app.UseDeveloperExceptionPage();
            }

            app.UseSession();
            app.UseRouting();
            app.UseDefaultFiles();
            app.UseStaticFiles();

            app.UseEndpoints(endpoints => {
                endpoints.MapControllers();
            });

        }
    }
}