Dependency Injection is a design pattern that is commonly used in object-oriented programming. It is a technique for managing the dependencies of objects, which makes it easier to build, test, and maintain software systems.
In Dependency Injection, instead of creating objects directly and passing them to other objects, the dependencies are injected into an object at runtime. This means that the objects do not need to be aware of how their dependencies are created, and they can be easily replaced or updated without affecting the rest of the system.
There are three main types of Dependency Injection:
- Constructor Injection: In this type, the dependencies are passed to the constructor of the object at the time of its creation.
- Setter Injection: In this type, the dependencies are injected into the object using setter methods.
- Interface Injection: In this type, the object implements an interface that defines the methods for setting the dependencies.
Dependency Injection is a powerful pattern that can help to reduce coupling between objects and improve the modularity of a software system. It is widely used in many popular frameworks, including Angular, Spring, and .NET Core.