Dependency Injection (DI) is a software design pattern in C# that allows objects to receive dependencies from external sources. Instead of creating dependencies internally, DI makes the code flexible, More maintainable, and testable.

Benefits of Dependency Injection

Here are some benefits of dependency:

Loose coupling

Dependency Injection reduces the tight coupling between software components, making code easier to maintain and reuse. Loose coupling means components are less dependent on each other and can operate more independently.

Modularization

Dependency Injection allows objects to depend on abstractions instead of concrete implementations.

Unit testing

Dependency, also known as Inversion-of-Control, is a principle of reversing the control of object creation from the class to an external source., it makes unit testing convenient.

Mock Objects

Dependency Injection allows for the use of "mock" objects to replace costly services.

Maintainability

Dependencies are managed centrally, making it easy to update or change the implementation.

In C#, Dependency Injection can be implemented in various ways, including constructor injection, property injection, and method injection.

Constructor Injection

It is a technique of dependency injection in C#, that passes dependencies to a class through its constructor.

csharp
📄
public class ServiceA
{
    private readonly IServiceB _serviceB;
    // Injecting the dependency via the constructor

    public ServiceA(IServiceB serviceB)
    {
        _serviceB = serviceB;
    }
    public void DoSomething()
    {
        _serviceB.PerformTask();
    }
}

Property Injection

It is a technique of dependency injection in C#, where dependencies are set through the property.

csharp
📄
public class ServiceA
{
     // Injected via property
    public IServiceB ServiceB { get; set; }
    public void DoSomething()
    {
        ServiceB?.PerformTask();
    }
}

Method Injection

It is also a technique of dependency injection in c#, dependencies are passed directly to methods that need them.

csharp
📄
public class ServiceA
{
    public void DoSomething(IServiceB serviceB) // Injecting directly into the method
    {
        serviceB.PerformTask();
    }
}