How to add Web API to an existing ASP.NET MVC 4 Web Application project?

Question

I wish to add an ASP.NET Web API to an ASP.NET MVC 4 Web Application project, developed in Visual Studio 2012. Which steps must I perform to add a functioning Web API to the project? I'm aware that I need a controller deriving from ApiController, but that's about all I know.

Let me know if I need to provide more details.

Answer 1

The steps I needed to perform were:

1. Add reference to System.Web.Http.WebHost.
2. Add App_Start\WebApiConfig.cs (see code snippet below).
3. Import namespace System.Web.Http in Global.asax.cs.
4. Call WebApiConfig.Register(GlobalConfiguration.Configuration) in MvcApplication.Application_Start() (in file Global.asax.cs), before registering the default Web Application route as that would otherwise take precedence.
5. Add a controller deriving from System.Web.Http.ApiController.

I could then learn enough from the tutorial (Your First ASP.NET Web API) to define my API controller.

App_Start\WebApiConfig.cs:

using System.Web.Http;  class WebApiConfig {     public static void Register(HttpConfiguration configuration)     {         configuration.Routes.MapHttpRoute("API Default", "api/{controller}/{id}",             new { id = RouteParameter.Optional });     } } 

Global.asax.cs:

using System.Web.Http;  ...  protected void Application_Start() {     AreaRegistration.RegisterAllAreas();      RegisterGlobalFilters(GlobalFilters.Filters);     WebApiConfig.Register(GlobalConfiguration.Configuration);     RegisterRoutes(RouteTable.Routes);     BundleConfig.RegisterBundles(BundleTable.Bundles); } 

Update 10.16.2015:

Word has it, the NuGet package Microsoft.AspNet.WebApi must be installed for the above to work.

Answer 2

UPDATE 11/22/2013 - this is the latest WebApi package:

Install-Package Microsoft.AspNet.WebApi 

Original answer (this is an older WebApi package)

Install-Package AspNetWebApi 

More details.