.NET Core: Use Dependency Injection for Loose Coupling – Bits of .NET

.NET Core: Use Dependency Injection for Loose Coupling

- 24.07.26 - ErcanOPAK

🔗 Dependency Injection = Loose Coupling

Tight coupling makes code inflexible. Dependency Injection decouples classes. Testable, maintainable, flexible.

❌ Tight Coupling

public class UserService
{
    private readonly EmailService _emailService;
    public UserService()
    {
        _emailService = new EmailService();
    }
}

✅ Dependency Injection

public class UserService
{
    private readonly IEmailService _emailService;
    public UserService(IEmailService emailService)
    {
        _emailService = emailService;
    }
}

📝 Register Services

// Program.cs
var builder = WebApplication.CreateBuilder(args);

// Transient: new instance every time
builder.Services.AddTransient();

// Scoped: new instance per request
builder.Services.AddScoped();

// Singleton: single instance (lifetime)
builder.Services.AddSingleton();

// Using DI in Controllers
[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    private readonly IUserService _userService;
    private readonly ILogger _logger;

    public UsersController(
        IUserService userService,
        ILogger logger)
    {
        _userService = userService;
        _logger = logger;
    }

    [HttpGet]
    public async Task GetUsers()
    {
        var users = await _userService.GetAllAsync();
        return Ok(users);
    }
}

# DI Tips
- Transient: lightweight, stateless
- Scoped: per request (web apps)
- Singleton: stateful, expensive
- Use interfaces for abstraction
- Follow Dependency Inversion Principle

💡 DI Tips

Transient: lightweight, stateless
Scoped: per request (web apps)
Singleton: stateful, expensive
Use interfaces for abstraction
Follow Dependency Inversion Principle

“DI makes code testable and maintainable. Loose coupling, flexible architecture. Essential for enterprise apps.”

— Software Architect

Related posts:

ASP.NET Core: Fix a Rate Limiter That Blocks Legitimate Traffic Behind a Shared Proxy IP

.NET Core — AddSingleton + State = Data Corruption

.NET Core Connection Pooling — The Hidden Performance Giant

Post Views: 4

Leave a Reply Cancel reply