tools-unity-vcontainer

VContainer Dependency Injection

Overview

VContainer is a lightweight, fast DI container for Unity. This skill covers registration patterns, lifecycle management, and common pitfalls that cause crashes.

When to Use

• Setting up dependency injection in Unity
• Creating scoped containers for features/states
• Debugging VContainerException crashes
• Writing testable Unity code
• Managing service lifetimes

Installation

// Package Manager
// Add to manifest.json:
"jp.hadashikick.vcontainer": "https://github.com/hadashiA/VContainer.git?path=VContainer/Assets/VContainer#1.15.4"

Core Concepts

Lifetime Types

Lifetime	Description	Use Case
Singleton	One instance per container	Global services, managers
Scoped	One instance per scope	Feature-specific services
Transient	New instance every resolve	Factories, short-lived objects

Critical: Singleton in a child scope is actually scoped to that child, not truly global!

Registration Patterns

Basic Registration

public class GameInstaller : LifetimeScope
{
    protected override void Configure(IContainerBuilder builder)
    {
        // Interface to implementation
        builder.Register<IPlayerService, PlayerService>(Lifetime.Singleton);
        
        // Concrete type
        builder.Register<GameManager>(Lifetime.Singleton);
        
        // With interfaces
        builder.Register<AudioSystem>(Lifetime.Singleton)
            .AsImplementedInterfaces()
            .AsSelf();
    }
}

Instance Registration

protected override void Configure(IContainerBuilder builder)
{
    // Pre-existing instance
    builder.RegisterInstance(existingService);
    
    // ScriptableObject from Resources
    var config = Resources.Load<GameConfig>("GameConfig");
    builder.RegisterInstance(config);
    
    // Component on same GameObject
    builder.RegisterComponent(GetComponent<AudioSource>());
}