When will you use this?

You use this in every web page and form you build from your first app to production.

• Product pages, login forms, and admin dashboards all use controllers, views, and models.
• When a user submits an order form, model binding maps form fields to a C# class.

Real-world: Toolliyo-style learning platform

The EdTech / LMS team building Toolliyo-style learning platform uses Controllers and Actions to handle GET /products and return the product list page or JSON. students and instructors never see the C# code — they just get a fast, reliable course API and lesson progress tracking.

Production-style code

public class ProductsController : Controller
{
    public IActionResult Index()
    {
        var products = new[] {
            new { Id = 1, Name = "Wireless Mouse", Price = 899 },
            new { Id = 2, Name = "USB-C Hub", Price = 1499 }
        };
        return View(products);
    }
}

What happens in production: In Toolliyo-style learning platform, getting Controllers and Actions right means students and instructors trust the course API and lesson progress tracking every day.

Lesson example (start here)

Copy this smaller example first. Once it works, compare it with the real-world code above.

public class ProductsController : Controller
{
    public IActionResult Index()
    {
        var products = new[] {
            new { Id = 1, Name = "Keyboard", Price = 2499m }
        };
        return View(products);
    }

    public IActionResult Details(int id)
    {
        return View();
    }
}

Line-by-line walkthrough

How it works (big picture)

• ProductsController handles /Products/...
• routes.
• Index returns a view.
• Details receives id from the URL.
• IActionResult can be a view, redirect, or JSON.

Do this on your computer

1. Add ProductsController with Index action.
2. Create Views/Products/Index.cshtml.
3. Browse to /Products and see your page.
4. Add Details(int id) and log the id.
5. Read the real-world section and name which part of the app uses this topic.
6. Run the example locally with dotnet run and confirm the same behavior.
7. Change one value in the example (route, text, or connection string) and predict what will happen before you save.

Experiments — try changing this

• Change a string or route in the example and save — watch the browser or Swagger response update.
• Break the code on purpose (remove a semicolon), read the error message, then fix it.

Remember

Controller = request handler class. Action = public method on that class. Return IActionResult for views or JSON.

Common questions