DEV Community

Rumen Dimov
Rumen Dimov

Posted on

Areas in ASP.NET Core: The Architectural Feature You're Probably Missing

#webdev #aspdotnet #csharp #dotnet

Introduction

If you've been working with ASP.NET Core and haven't encountered Areas yet, you're not alone. Despite being a powerful organisational feature, Areas are often overlooked in tutorials and beginner resources. This oversight leads many developers to create convoluted controller hierarchies and strange architectural patterns that Areas were specifically designed to solve.

I've seen projects where developers create "super controllers" or awkward folder structures trying to achieve what Areas provide out of the box. Let's fix that.

What Are Areas?

Areas are a feature in ASP.NET Core that allow you to partition your web application into smaller functional groups. Each area represents a distinct section of your application with its own set of controllers, views, and models. Think of them as mini-MVC applications within your main application.

Why Areas Matter

1. Logical Organisation

Without Areas, large applications often end up with dozens of controllers in a single folder, making navigation and maintenance a nightmare. Areas let you group related functionality together.

2. Team Collaboration

Different teams can work on different areas without stepping on each other's toes. The Admin team works in the Admin area, the API team in the API area, and so on.

3. Namespace Separation

Areas provide automatic namespace separation, preventing naming conflicts and making your code more maintainable.

4. Route Management

Areas provide built-in route segregation, making your URL structure cleaner and more intuitive.

Real-World Example: E-Commerce Application

Let's say you're building an e-commerce platform. Without Areas, you might have:

Controllers/
├── HomeController.cs
├── ProductController.cs
├── CategoryController.cs
├── AdminProductController.cs
├── AdminCategoryController.cs
├── AdminUserController.cs
├── AdminDashboardController.cs
├── CustomerOrderController.cs
├── CustomerProfileController.cs
└── ... (dozens more)
Enter fullscreen mode Exit fullscreen mode

This quickly becomes unmanageable. With Areas, you get:

Areas/
├── Admin/
│   ├── Controllers/
│   │   ├── ProductController.cs
│   │   ├── CategoryController.cs
│   │   ├── UserController.cs
│   │   └── DashboardController.cs
│   ├── Views/
│   └── Models/
├── Customer/
│   ├── Controllers/
│   │   ├── OrderController.cs
│   │   └── ProfileController.cs
│   ├── Views/
│   └── Models/
└── Public/
    ├── Controllers/
    │   ├── HomeController.cs
    │   ├── ProductController.cs
    │   └── CategoryController.cs
    ├── Views/
    └── Models/
Enter fullscreen mode Exit fullscreen mode

Implementing Areas

Step 1: Create an Area
// Create folder structure:
// Areas/Admin/Controllers/
// Areas/Admin/Views/
// Areas/Admin/Models/

Step 2: Configure the Controller

namespace YourApp.Areas.Admin.Controllers
{
    [Area("Admin")]
    [Route("Admin/[controller]/[action]")]
    public class DashboardController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }
    }
}
Enter fullscreen mode Exit fullscreen mode

Step 3: Update Startup Configuration

app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
            name: "areas",
            pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}");

        endpoints.MapControllerRoute(
            name: "default",
            pattern: "{controller=Home}/{action=Index}/{id?}");
    });
Enter fullscreen mode Exit fullscreen mode

Common Pitfalls and Solutions

The "God Controller" Anti-Pattern

Without Areas, developers often create controllers like AdminController with dozens of actions for all administrative functions. This violates the Single Responsibility Principle and makes testing difficult.
Solution: Use an Admin area with focused controllers for each entity or feature.

View Location Issues

Areas have their own view locations. If your views aren't rendering, check that they're in the correct area folder.

Areas/Admin/Views/Dashboard/Index.cshtml
Enter fullscreen mode Exit fullscreen mode

Routing Conflicts

Be explicit with your routes to avoid conflicts between areas and main application routes.

[Area("Admin")]
[Route("admin/[controller]/[action]")]
public class ProductController : Controller
{
    // Accessible at: /admin/product/index
}
Enter fullscreen mode Exit fullscreen mode

Advanced Tips

Area-Specific Layouts

Create area-specific layouts to give different sections of your application distinct looks:

Areas/Admin/Views/Shared/_Layout.cshtml
Enter fullscreen mode Exit fullscreen mode

Authorization by Area

Apply authorization policies at the area level:

[Area("Admin")]
[Authorize(Policy = "AdminOnly")]
public class BaseAdminController : Controller
{
    // All admin controllers inherit from this
}
Enter fullscreen mode Exit fullscreen mode

Conclusion

Areas are one of ASP.NET Core's most underutilised features. They provide a clean, maintainable way to organise large applications without resorting to architectural gymnastics. Before you create that SuperAdminController or implement your own module system, consider whether Areas might be the solution you're looking for.
Next time you start a new ASP.NET Core project that's going to grow beyond a handful of controllers, set up your Areas from the beginning. Your future self (and your team) will thank you.

Further Reading

Have you used Areas in your projects? What patterns have you found helpful? Share your experiences in the comments below!

Top comments (0)