Startup.cs

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Bot.Builder;
using Microsoft.Bot.Builder.BotFramework;
using Microsoft.Bot.Builder.Integration.AspNet.Core;
using Microsoft.Bot.Connector.Authentication;
using Microsoft.Bot.Schema;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.Teams.App.Mapper.Bots;
using Microsoft.Teams.App.Mapper.Dialogs;

namespace Microsoft.Teams.App.Mapper
{
    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().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            // Create the Bot Framework Adapter with error handling enabled. 
            services.AddSingleton<IBotFrameworkHttpAdapter, AdapterWithErrorHandler>();

            // Create the storage we'll be using for User and Conversation state. (Memory is great for testing purposes.) 
            services.AddSingleton<IStorage, MemoryStorage>();

            // Create the User state. (Used in this bot's Dialog implementation.)
            services.AddSingleton<UserState>();

            // Create the Conversation state. (Used by the Dialog system itself.)
            services.AddSingleton<ConversationState>();

            // Create a global hashset for our ConversationReferences
            services.AddSingleton<ConcurrentDictionary<string, ConversationReference>>();

            //// The Dialog that will be run by the bot.
            services.AddSingleton<MainDialog>();

            // Create the bot as a transient. In this case the ASP Controller is expecting an IBot.
            services.AddTransient<IBot, MapperBot>();

        }

        // 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();
            }
            else
            {
                // 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.UseMvc();
        }
    }
}