Design Patterns in C# (Factory, Singleton, Repository, Observer)

Originally published at https://allcoderthings.com/en/article/csharp-design-patterns-factory-singleton-repository-observer Design Patterns provide standard and proven solutions for recurring problems in software development. Commonly used patterns in C# include Factory, Singleton, Repository, Observer, Strategy, Adapter, and Decorator. This article explores the core concepts of these patterns, their use cases, and C# examples. Factory Pattern The Factory pattern centralizes object creation. Instead of using new everywhere, the responsibility of creating objects is delegated to a factory class. public interface IProduct { void DoWork(); } public class ProductA : IProduct { public void DoWork() => Console.WriteLine("Product A"); } public class ProductB : IProduct { public void DoWork() => Console.WriteLine("Product B"); } public static class ProductFactory { public static IProduct Create(string type) => type switch { "A" => new ProductA(), "B" => new ProductB(), _ => th