Type registered with Singleton instantiating multiple times

[furqansafdar]

How can i ensure that RuleMenuOptionItem type only instantiate one time?

internal class Program
{
    static void Main(string[] args)
    {
        var container = new Container();

        // Registering singletons
        container.Register<RuleMenuOptionItem>(Reuse.Singleton);
        container.Register<INavMenuItem, RuleMenuOptionItem>(Reuse.Singleton);

        // Resolve instances
        var instance1 = container.Resolve<RuleMenuOptionItem>();
        var instance2 = container.Resolve<INavMenuItem>();
        var lazyInstance = container.Resolve<Lazy<IEnumerable<INavMenuItem>>>();

        // Check if instances are the same
        Console.WriteLine(ReferenceEquals(instance1, instance2)); // Should be True

        // Trigger Lazy loading
        var lazyItems = lazyInstance.Value;
        foreach (var item in lazyItems)
        {
            Console.WriteLine(item.GetType().Name);
        }
    }
}

public interface INavMenuItem { }

public class RuleMenuOptionItem : INavMenuItem
{
    private static int _instanceCount = 0;
    public RuleMenuOptionItem()
    {
        _instanceCount++;
        Console.WriteLine($"RuleMenuOptionItem instantiated {_instanceCount} times");
    }
}

[dadhi]

@furqansafdar

Replace the registration with RegisterMany:

        // Registering singletons
        container.Register<RuleMenuOptionItem>(Reuse.Singleton);
        container.Register<INavMenuItem, RuleMenuOptionItem>(Reuse.Singleton);

with

        container.RegisterMany<RuleMenuOptionItem>(Reuse.Singleton);

Check the docs.

[furqansafdar]

Yes, this is working thanks. However, I came across another approach from here and worked.

container.Register<RuleMenuOptionItem>(Reuse.Singleton);
container.Register<IHamburgerNavMenuItem, RuleMenuOptionItem>(made: Made.Of(() => ReturnThis(Arg.Of<RuleMenuOptionItem>())), reuse: Reuse.Singleton);

static T ReturnThis<T>( T t ) => t;

What is the difference between the two if you can briefly elaborate for better understanding? Further, is there any article to learn more about it.

[dadhi]

The one with Made.Of has more overhead without any benefits for your specific case. RegisterMany is specifically designed for your case. Another viable option is to use RegisterMapping, which designed to add services to the already registered implementation.