ASP.NET - Dependency Injection (DI)

Dependency Injection is a design pattern that removes hard dependencies between classes. ASP.NET Core has built-in DI support.

Services are registered in the container and injected where needed. This promotes loose coupling and testability.

ASP.NET supports service lifetimes: Singleton, Scoped, and Transient. Choosing the wrong lifetime causes bugs and memory leaks.

DI enables unit testing by allowing mock implementations.

Modern ASP.NET applications are impossible to maintain without proper DI usage.