Ninject: What does it mean to bind something to itself?

Question

Ninject has the functionality of self binding like Bind<Samurai>().ToSelf();

I read about this but I don't get the importance or how this can be useful. Any comments are appreciated.

Dennison

Answer 1

If Ninject finds a object that needs to be created and it has a constructor that has a Samurai parameter it does not know how to instantiate it.

But when you use Bind<Samurai>().ToSelf(); then Ninject knows that a Samurai needs to be created to pass to the Samurai parameter.

If that binding was not there then ninject didn't know what to pass, for example there might have been a SamuraiSubClass type. But by explicitly saying that when Ninject finds a Samurai parameter that it needs to create a Samurai for that parameter then Ninject knows exactly what to do.

Cynewulf

Why not just explicitly say what to bind Samurai ? – Guyon

Bind<Samurai>().To<Samurai>(); is the same as Bind<Samurai>().ToSelf(); it just reads better – Cynewulf

Ok I see so it is not just interfaces that you can inject you can also inject concrete types – Guyon

Indeed, or abstract classes – Cynewulf

Answer 2

I use the .WithConstructorArgument() quite a bit. Bind<Samurai>().ToSelf().WithConstructorArgument("owner", user); Just a nice way to provide an object(s) to your Samuari constructor when it is being injected.

Bessette