The type or namespace IHttpActionResult not found

Question

This is the first time I am creating a Web API application in ASP.NET MVC4. I opened a new Web API project and added a new controller named \'Product\'. The function given below

Answer 1

I had similar problem & re installation will solve this issue. Just go to Tools > NuGet Package Manager > Package Manager Console in Visual Studio 2013 and write down the following :-

PM> update-Package Microsoft.AspNet.WebApi –reinstall

Then, Clean the solution and Build/Rebuild the solution.

Note: In my case, the process explicitly checked out Web.config and packages.config file and also removed the System.Web.Http dll file.