Injecting array of concrete classes always contains a single element

[slaneyrw]

I'm converting an application from Unity to Ninject but I've hit an issue that I cannot find any doco on.

I have a class that has a constructor parameter that is an Array of a concrete class. Unity will inject an empty array if I haven't explicitly registered named instances.

Ninject, on the other hand, will construct an instance of the concrete and give me an array with 1 element.
At the bottom of https://github.com/ninject/Ninject/wiki/Dependency-Injection-With-Ninject, it states that I should be able to inject 0..n.

Is an empty array only possible with interfaces ?

I cannot change the constructor signature, so is it possible to inject an empty array if no implementations of the concrete type are bound ?

[BrunoJuchli]

With T[], List<T> and IEnumerable<T> multi injection takes precedence. If there is no Bindings for T (like Bind<T>()...) then ninject checks whether T is "self-bindable" (i.E. an instantiatable class), if so, it will create an instance of T.

So if T is an abstract class injecting an empty array is possible, too - because in that case T is not "self-bindable".

Short of making T abstract (or maybe changing it's ctors visibility, if that's possible?) the only remedies i can think of is adapting the binding of X where T[] is injected, either using ToConstructor, ToMethod, ToProvider - or mabe with an argument/parameter. Maybe you could also roll your own IParameter which resolves all the Ts by IResolutionRoot.GetAll.

[slaneyrw]

Thanks, I'll look at the custom IParameter route

[scott-xu]

Fixed by bf47cc9