Let's create a controller for the api/questions endpoint. If we don't have our backend project open in Visual Studio, let's do so and carry out the following steps:

1. In Solution Explorer, right-click on the Controllers folder, choose Add, and then Class....
2. In the left-hand panel, find and select ASP.NET Core and then API Controller Class in the middle panel. Enter QuestionsController.cs for the name of the file and click Add:

3. If the generated class doesn't inherit from ControllerBase, let's add this and remove the example action methods:

public class QuestionsController : ControllerBase
{
       
}

ControllerBase will give us access to more API-specific methods in our controller.

4. If the generated class isn't decorated with the Route and ApiController attributes, let's add them:

[Route("api/[controller]")]
[ApiController]
public class QuestionsController : ControllerBase
{
       
}

The Route attribute defines the path that our controller will handle. In our case, the path will be api/questions because [controller] is substituted with the name of the controller minus the word controller.

The ApiController attribute includes behavior such as automatic model validation, which we'll take advantage of later in this chapter.