Now that you've seen the basics of how models, views, and controllers work together to provide a web application, let's look at some common scenarios, such as passing parameters and annotating models.
Back in the HomeController class, add the following action method. It uses a class called defaultmodelbinder to automatically match the id passed in the route to the parameter named id in the method.
Note
Model binders are very powerful, and the default one does a lot for you. For advanced scenarios, you can create your own by implementing the IModelBinder interface, but that is beyond the scope of this book.
Inside the method, we check to see whether id is null, and if so, it returns a 404 status code and message. Otherwise, we can connect to the database and try to retrieve a product using the id variable. If we find a product, we pass it to a view; otherwise, we return a different 404 status code and message, as shown in the...