C# Architecture Best Practices

Design robust and scalable C# applications by following these architecture best practices.

Use Dependency Injection

Important

Implement dependency injection to create loosely coupled, testable code.

Recommended Approach

// Good
public class OrderService
{
    private readonly IPaymentProcessor _paymentProcessor;
    private readonly IEmailService _emailService;
    
    public OrderService(IPaymentProcessor paymentProcessor, IEmailService emailService)
    {
        _paymentProcessor = paymentProcessor;
        _emailService = emailService;
    }
}

Avoid This Approach

// Bad
public class OrderService
{
    private readonly PaymentProcessor _paymentProcessor = new PaymentProcessor();
    private readonly EmailService _emailService = new EmailService();
}

Implement Microservices Architecture

Critical

Design your application as a collection of loosely coupled services to improve scalability and maintainability.

Recommended Approach

// Good
public class OrderService
{
    public void ProcessOrder(Order order)
    {
        // Logic to process order
    }
}

// Microservice setup
public class OrderMicroservice
{
    private readonly OrderService _orderService;

    public OrderMicroservice(OrderService orderService)
    {
        _orderService = orderService;
    }

    public void Start()
    {
        // Start microservice
    }
}

Avoid This Approach

// Bad
public class MonolithicOrderProcessor
{
    public void ProcessOrder(Order order)
    {
        // Logic to process order
        // All logic in one place
    }
}

Use Event-Driven Architecture

Important

Implement event-driven architecture to decouple components and improve responsiveness.

Recommended Approach

// Good
public class EventPublisher
{
    public void PublishEvent(Event event)
    {
        // Logic to publish event
    }
}

public class EventSubscriber
{
    public void Subscribe()
    {
        // Logic to subscribe to events
    }
}

Avoid This Approach

// Bad
public class TightlyCoupledComponent
{
    public void Execute()
    {
        // Direct calls to other components
    }
}

Implement Domain-Driven Design (DDD)

Critical

Use DDD to align your software model with business needs and improve communication between technical and non-technical stakeholders.

Recommended Approach

// Good
public class CustomerAggregate
{
    public void AddOrder(Order order)
    {
        // Logic to add order to customer
    }
}

Avoid This Approach

// Bad
public class Customer
{
    public void AddOrder(Order order)
    {
        // Logic scattered across multiple classes
    }
}

Adopt a Layered Architecture

Important

Structure your application into layers (e.g., presentation, business, data) to separate concerns and improve maintainability.

Recommended Approach

// Good
public class PresentationLayer
{
    public void DisplayData()
    {
        // Logic to display data
    }
}

public class BusinessLayer
{
    public void ProcessData()
    {
        // Logic to process data
    }
}

Avoid This Approach

// Bad
public class MonolithicApplication
{
    public void Execute()
    {
        // All logic in one place
    }
}

Implement CQRS (Command Query Responsibility Segregation)

Important

Separate the read and write operations of your application to optimize performance and scalability.

Recommended Approach

// Good
public class CommandHandler
{
    public void HandleCommand(Command command)
    {
        // Logic to handle command
    }
}

public class QueryHandler
{
    public TResult HandleQuery<TResult>(Query query)
    {
        // Logic to handle query
        return default(TResult);
    }
}

Avoid This Approach

// Bad
public class UnifiedHandler
{
    public void HandleRequest(Request request)
    {
        // Mixed logic for handling commands and queries
    }
}

Use API Gateway Pattern

Critical

Implement an API Gateway to manage and route requests to various microservices, providing a single entry point.

Recommended Approach

// Good
public class ApiGateway
{
    public void RouteRequest(Request request)
    {
        // Logic to route request to appropriate microservice
    }
}

Avoid This Approach

// Bad
public class DirectClientAccess
{
    public void AccessService(Service service)
    {
        // Direct access to microservices without a gateway
    }
}

Adopt Semantic Versioning

Important

Use semantic versioning (MAJOR.MINOR.PATCH) to communicate changes in your API or software effectively.

Recommended Approach

// Good
// Version 1.0.0 - Initial release
// Version 1.1.0 - Added new features
// Version 2.0.0 - Breaking changes introduced

Avoid This Approach

// Bad
// Version 1 - Initial release
// Version 2 - Added new features and breaking changes

Version Your APIs

Critical

Ensure your APIs are versioned to manage changes and maintain backward compatibility.

Recommended Approach

// Good
// API v1
[Route("api/v1/products")]
public IActionResult GetProductsV1()
{
    // Logic for version 1
}

// API v2
[Route("api/v2/products")]
public IActionResult GetProductsV2()
{
    // Logic for version 2
}

Avoid This Approach

// Bad
// No versioning
[Route("api/products")]
public IActionResult GetProducts()
{
    // Logic without versioning
}

Document Version Changes

Important

Maintain a changelog to document changes, bug fixes, and updates for each version.

Recommended Approach

// Good
// Changelog
// Version 1.0.0 - Initial release
// Version 1.1.0 - Added feature X
// Version 1.1.1 - Fixed bug Y

Avoid This Approach

// Bad
// No changelog
// Users are unaware of changes and updates

Deprecate Old Versions Gracefully

Critical

Provide clear deprecation notices and timelines for phasing out old versions.

Recommended Approach

// Good
// Deprecation notice
// API v1 will be deprecated on 2023-12-31
// Please migrate to API v2

Avoid This Approach

// Bad
// No deprecation notice
// Users are caught off guard by sudden changes

Implement Feature Toggles

Important

Use feature toggles to manage the release of new features without deploying a new version.

Recommended Approach

// Good
public class FeatureToggle
{
    public bool IsFeatureXEnabled { get; set; }

    public void ToggleFeatureX()
    {
        // Logic to enable/disable feature X
    }
}

Avoid This Approach

// Bad
// No feature toggles
// New features require a full deployment

Use Version Control Branching Strategies

Critical

Adopt branching strategies like Git Flow or trunk-based development to manage version control effectively.

Recommended Approach

// Good
// Git Flow
// - master: production-ready code
// - develop: latest development changes
// - feature branches: new features

Avoid This Approach

// Bad
// No branching strategy
// Code changes are made directly to the main branch