A well-designed ASP.NET MVC/.NET application follows the Separation of Concerns (SoC) principle. The Model manages data and business rules, the View handles the user interface, and the Controller processes requests and coordinates communication between the Model and View. For larger applications, business logic should be placed in a Service Layer, while database operations belong in a Repository Layer using Entity Framework. Implement Dependency Injection for loose coupling, Authentication and Authorization for security, and centralized Logging and Exception Handling for reliability. Organize the project into clear folders, use configuration files properly, and follow SOLID principles to ensure scalability, maintainability, and testability.
Designing the architecture of an ASP.NET MVC/.NET application requires separating responsibilities, making the application maintainable, testable, scalable, and easy to extend. One of the most widely adopted approaches is Layered Architecture combined with Dependency Injection and common design patterns such as Repository, Unit of Work, and Service Layer.
+----------------------+
| Presentation |
| ASP.NET MVC / Razor |
+----------+-----------+
|
v
+----------------------+
| Business Layer |
| Services / Managers |
+----------+-----------+
|
v
+----------------------+
| Data Access Layer |
| Repository / EF Core |
+----------+-----------+
|
v
+----------------------+
| Database |
| SQL Server/MySQL |
+----------------------+
This layer interacts with users.
Responsibilities
Example
public class ProductController : Controller
{
private readonly IProductService _service;
public ProductController(IProductService service)
{
_service = service;
}
public IActionResult Index()
{
var products = _service.GetAllProducts();
return View(products);
}
}
The controller should never directly communicate with the database.
Example
public class ProductService : IProductService
{
private readonly IProductRepository _repository;
public ProductService(IProductRepository repository)
{
_repository = repository;
}
public IEnumerable<Product> GetAllProducts()
{
return _repository.GetAll();
}
}
Benefits
Responsible for database communication.
Example
public class ProductRepository : IProductRepository
{
private readonly ApplicationDbContext _context;
public ProductRepository(ApplicationDbContext context)
{
_context = context;
}
public IEnumerable<Product> GetAll()
{
return _context.Products.ToList();
}
}
Repository hides Entity Framework details from the business layer.
Stores
Example
Products
---------
Id
Name
Price
CategoryId
Stock
Contains
Product
Category
Order
Customer
Invoice
Employee
Example
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
}
Never expose database entities directly to Views.
Example
public class ProductViewModel
{
public string Name { get; set; }
public decimal Price { get; set; }
public bool IsAvailable { get; set; }
}
Benefits
Instead of creating objects manually
Bad
var service = new ProductService();
Use DI
public ProductController(IProductService service)
{
_service = service;
}
Registration
builder.Services.AddScoped<IProductRepository, ProductRepository>();
builder.Services.AddScoped<IProductService, ProductService>();
Benefits
Instead of writing SQL everywhere
Controller
↓
Repository
↓
Entity Framework
↓
Database
Example Interface
public interface IProductRepository
{
IEnumerable<Product> GetAll();
Product GetById(int id);
void Add(Product product);
void Update(Product product);
void Delete(int id);
}
If multiple repositories need to be saved together
OrderRepository
CustomerRepository
InvoiceRepository
↓
Unit Of Work
↓
Save()
Example
public interface IUnitOfWork
{
IProductRepository Products { get; }
IOrderRepository Orders { get; }
void Save();
}
These should be reusable across the application.
Logging
Caching
Authentication
Authorization
Exception Handling
Validation
Email Service
File Upload
Configuration
Use
Example
_logger.LogInformation("Product Added Successfully");
Use middleware or filters.
try
{
service.AddProduct(product);
}
catch(Exception ex)
{
_logger.LogError(ex.Message);
}
Use
Use Data Annotations.
public class ProductViewModel
{
[Required]
public string Name { get; set; }
[Range(1,10000)]
public decimal Price { get; set; }
}
Solution
│
├── Web
│ ├── Controllers
│ ├── Views
│ ├── ViewModels
│ ├── Filters
│ └── Middleware
│
├── Business
│ ├── Services
│ ├── Interfaces
│ └── DTOs
│
├── Data
│ ├── Repositories
│ ├── DbContext
│ ├── Configurations
│ └── Migrations
│
├── Domain
│ ├── Entities
│ ├── Enums
│ ├── ValueObjects
│ └── Interfaces
│
├── Infrastructure
│ ├── Logging
│ ├── Email
│ ├── Cache
│ └── Identity
│
└── Tests
├── UnitTests
└── IntegrationTests
Browser
│
Controller
│
Service Layer
│
Repository
│
Entity Framework
│
SQL Server
│
Repository
│
Service
│
Controller
│
View
│
Browser
async/await) for I/O-bound operations to improve scalability.For new ASP.NET Core MVC applications, a variation of Clean Architecture is often preferred over a simple layered architecture because it enforces clearer boundaries and better testability.
Presentation (MVC)
│
▼
Application (Use Cases, DTOs, Validation)
│
▼
Domain (Entities, Business Rules)
│
▲
Infrastructure (EF Core, Email, Logging, External APIs)
│
▼
Database
This approach keeps the Domain and Application layers independent of frameworks such as Entity Framework or ASP.NET Core, making the application easier to maintain and evolve as requirements grow.
