testapps/ContosoUniversityWeb/Startup.cs

using ContosoUniversity.Data;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

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

        public IConfiguration Configuration { get; }

        #region snippet_ConfigureServices
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();

            services.AddDbContext<SchoolContext>(options =>
               options.UseSqlServer(Configuration.GetConnectionString("SchoolContext")));

            services.AddDatabaseDeveloperPageExceptionFilter();
        }
        #endregion

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
           // if (env.IsDevelopment())
           // {
                app.UseDeveloperExceptionPage();
           // }
           // else
           // {
           //     app.UseExceptionHandler("/Error");
           //     app.UseHsts();
           // }

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

            app.UseRouting();

            app.UseAuthorization();

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