Unity Dependency Injection

Unity Dependency Injection (DI)

A lightweight system to satisfy the "D" in SOLID. Allows classes to request dependencies via [Inject] without knowing who provides them.

Core Features

1. Attribute-Based Injection: Use [Inject] to mark fields and [Provide] to define sources.
2. Interface Focus: Encourages programming to abstractions, making systems hot-swappable.
3. Automated Wiring: Scene-wide injection happens on Awake, ensuring dependencies are ready before Start.
4. Diagnostic Logging: Tracks successful injections and warns about missing providers.

Core Files (Max 3)

• DIAttributes.cs.txt: Contains the marker attributes for the compiler.
• DependencyInjector.cs.txt: The engine that finds and wires dependencies in the scene.
• DIExample.cs.txt: Shows how to decouple a Hero from an AbilitySystem.

Usage

1. Define an Interface

public interface IWeapon { void Fire(); }

2. Provide the Implementation

public class PlasmaRifle : MonoBehaviour, IWeapon {
    [Provide] public IWeapon GetWeapon() => this;
    public void Fire() { /* ... */ }
}

3. Inject into Client

public class Player : MonoBehaviour {
    [Inject] private IWeapon currentWeapon;
    void Start() => currentWeapon.Fire();
}

4. Setup

Place a DependencyInjector component in your scene or persistent prefab.