Register with Keys

When you need to register multiple implementations of the same interface or type, you can use keys to distinguish them. VContainer supports keys of any type.

// Register with enum keys
public enum WeaponType
{
    Primary,
    Secondary,
    Special
}

builder.Register<IWeapon, Sword>(Lifetime.Singleton)
    .Keyed(WeaponType.Primary);

builder.Register<IWeapon, Bow>(Lifetime.Singleton)
    .Keyed(WeaponType.Secondary);

builder.Register<IWeapon, MagicStaff>(Lifetime.Singleton)
    .Keyed(WeaponType.Special);

// Register with string keys
builder.Register<IEnemy, Goblin>(Lifetime.Singleton)
    .Keyed("goblin");

builder.Register<IEnemy, Orc>(Lifetime.Singleton)
    .Keyed("orc");

// Register with integer keys
builder.Register<ILevel, Level1>(Lifetime.Singleton)
    .Keyed(1);

builder.Register<ILevel, Level2>(Lifetime.Singleton)
    .Keyed(2);

To resolve keyed registrations, use the Key attribute in injection or the container API directly:

class WeaponSystem
{
    public WeaponSystem(
        [Key(WeaponType.Primary)] IWeapon primaryWeapon,
        [Key(WeaponType.Secondary)] IWeapon secondaryWeapon)
    {
        // ...
    }
}

See the Key Attribute section for more information on using keys in injection.

note

You might think that this feature allows you to DI anything, but we do not recommend injection fine-grained values. Generally, consider creating a factory or provider first and then DI it. It is good practice to consider using a key if it is clearly an unnecessary abstraction or if for some reason it cannot be done.

Register with Keys​

Register with Keys