For last couple of days I am searching for some tutorials about how to call a Stored Procedure from inside a Web API controller method using
DbContext has a Database property, which holds a connection to the database that you can do whatever you want with:
context.Database.SqlQuery("exec [dbo].[GetFoo] @Bar = {0}", bar);
However, rather than doing this in your Web Api actions, I would suggest either adding a method to your context or to whatever service/repository that interacts with your context. Then just call this method in your action. Ideally, you want to keep all your SQL-stuff in one place.