We just enabled and wired up the MVC service to our application. Now, let's add a Web API controller by following these steps:

1. Right-click on the My Todo project, navigate to Add | New Folder, and name the folder Controllers:

2. Now, right-click on the Controllers folder that we just created and go to Add | New Item:

3. Select Minimal Dependencies and click on Add if you get an Add MVC Dependencies popup:

Visual Studio 2017 has added a ScaffoldingReadMe.txt readme file with the following instructions to enable scaffolding in our application; follow and update your project code accordingly.

ASP.NET MVC core dependencies have been added to the project. However, you may still need to make these changes to your project:

1. Add Scaffolding CLI tool to the project:

    <ItemGroup>   
     <DotNetCliToolReference    
     Include="Microsoft.VisualStudio.Web.CodeGeneration.  
     Tools"  Version="1.0.0" />   
    </ItemGroup>   

2. These are the suggested changes to the Startup class:

    2.1 Add a constructor:   
        public IConfigurationRoot   Configuration { get; }   
        public Startup(IHostingEnvironment   env)   
        {   
            var builder = new   ConfigurationBuilder()   
                .SetBasePath(env.ContentRootPath)   
                .AddJsonFile("appsettings.json",     
                 optional: true, 
                    reloadOnChange: true)   
                .AddJsonFile($"appsettings.
                 {env.EnvironmentName}.json",   optional: 
                  true)   
                .AddEnvironmentVariables();   
            Configuration =   builder.Build();   
        }   
    2.2 Add MVC services:   
        public void   ConfigureServices(IServiceCollection  
        services)   
        {   
            // Add framework   services.   
            services.AddMvc();   
       }   
    2.3 Configure web app to use   use Configuration and 
        use MVC routing:  
        public void   Configure(IApplicationBuilder app, 
        IHostingEnvironment env, ILoggerFactory   
        loggerFactory)   
        {      
        loggerFactory.AddConsole(Configuration.GetSection       
        ("Logging"));   
              loggerFactory.AddDebug();  
            if (env.IsDevelopment())   
            {   
                  app.UseDeveloperExceptionPage();   
            }   
            else   
            {   
                  app.UseExceptionHandler("/Home/Error");   
            }   
            app.UseStaticFiles();   
   
            app.UseMvc(routes   =>   
            {   
                routes.MapRoute(   
                    name: "default",   
                    template: " 
            {controller=Home}/{action=Index}
                     /{id?}");   
            });   
        }

3. Again, right-click on the Controllers folder, go to Add | Controllers, select API Controller with read/write actions, and name it as TodosController:

This is the error:

The following is the code for the XML tag:

<ItemGroup>   
          <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools"   Version="1.0.1" />   
</ItemGroup>   

This will create the TodosController Web API controller with the following template code for us to modify according to our needs:

[Produces("application/json")]   
    [Route("api/Todos")]   
    public class TodosController   : Controller   
    {   
        // GET: api/Todos   
        [HttpGet]   
        public   IEnumerable<string> Get()   
        {   
            return new string[] {   "value1", "value2" };   
        }  
        // GET: api/Todos/5   
        [HttpGet("{id}", Name = "Get")]   
        public string Get(int id)   
        {   
            return "value";   
        }    
        // POST: api/Todos   
        [HttpPost]   
        public void   Post([FromBody]string value)   
        {   
        }   
        // PUT: api/Todos/5   
        [HttpPut("{id}")]   
        public void Put(int id,   [FromBody]string value)   
        {   
        }   
        // DELETE:   api/ApiWithActions/5   
        [HttpDelete("{id}")]   
        public void Delete(int   id)   
        {   
        }   
    }   

4. Press F5 to run the application and navigate to http://localhost:2524/api/todos from the browser.

You will see the following output from TodosController as per the default code in the Get method. As you can see in the following screenshot, it just returned an array of string: