C-Sharp

TL;DR ISP means interfaces should be small and focused on client needs. Avoid “God” interfaces that force clients to implement unused methods. Split large interfaces into cohesive, role-based interfaces. Use C# 12 features like default interface methods for flexibility. ISP improves maintainability, testability, and reduces coupling. Refactor fat interfaces by extracting related methods into separate interfaces. Interface Segregation Principle stops you from creating huge interfaces that force clients to implement methods they’ll never use. When interfaces get too big, your implementations end up filled with empty methods and unnecessary dependencies. ...

A comprehensive guide to diagnosing and fixing common EF Core performance issues, with practical code examples and real-world performance improvements.

Learn why preferring interfaces over abstract classes in C# improves code flexibility, testability, and maintainability for robust .NET applications.

Master IEquatable in C# to optimize equality checks, improve collection performance, and eliminate boxing overhead. Essential for value types and collections.

Learn how polymorphism in C# using Template Method, Strategy, and Visitor patterns makes your code flexible, maintainable, and reusable.

A practical guide to C# Default Interface Methods: how to use them, when to avoid them, and how they help you build future-proof APIs.

TL;DR LSP means you can use subtype objects anywhere you use base type objects without breaking code. Square/Rectangle inheritance that breaks existing code? That’s a classic LSP problem. Watch for subclasses that throw unexpected exceptions or silently change behavior. When behaviors are too different, reach for composition instead of inheritance. Make interfaces that clearly show what objects can and can’t do to avoid surprises. LSP violations often sneak past unit tests and show up as runtime bugs. The Liskov Substitution Principle isn’t just academic theory - it helps you avoid those “it worked yesterday” bugs that show up in production. When a subclass doesn’t behave like its parent promises, your code breaks in ways that unit tests often miss. ...

Discover how the Dependency Inversion Principle makes your C# code flexible and testable. Learn to use ASP.NET Core DI to depend on abstractions, swap implementations, and build maintainable, scalable applications with real-world examples.

Discover the best practices for encapsulation in C#. Learn when to use auto-properties, when to switch to backing fields, and how to keep your property setters clean, focused, and maintainable with practical examples and actionable guidelines.

TL;DR: The Open/Closed Principle (OCP) states: classes should be open for extension, but closed for modification. You don’t need to create a plugin for every new feature, favor simpler patterns like strategy, inheritance, or composition. Start with well-named abstractions; introduce extensibility points only when real change is expected. Keep code maintainable by balancing extension points with simplicity. Overengineering is a bigger risk than occasional refactoring. The Open/Closed Principle isn’t about making everything extensible. It simply means that your core business logic should be closed to modification but open to extension. The real skill is knowing when to apply it and when you’re just over-engineering your code. ...