Dependency Injection Basics in C#

In software development, Dependency Injection (DI) is an important design pattern used to manage dependencies. With DI, classes receive the objects they need from the outside instead of creating them internally. This makes code more flexible, testable, and maintainable. In the C# and .NET Core ecosystem, DI is supported out of the box. What is a Dependency? A class depends on another class when it requires its functionality. For example, an OrderService may need an ILogger instance when creating an order. If OrderService directly uses new Logger() , it becomes tightly coupled to the Logger class. public class OrderService { private readonly Logger _logger = new Logger (); public void CreateOrder ( string product ) { _logger . Log ( $"Order created: { product } " ); } } public class Logger { public void Log ( string message ) => Console . WriteLine ( message ); } In this approach, the Logger cannot be replaced. If you want to use a different logging system, you must modify the OrderServ