没有C的参考项目B

Question

I have three projects A, B and C. These are connected together like so:

A -> B -> C

If project C has a base like so:

public class CBaseClass
{
    public string Name { get; set; }
}

and project B has an inheriting class like so:

public class BInheritingClass : CBaseClass
{

}

How can I access BInheritingClass.Name in project A without it giving me the following error:

The type 'CBaseClass' is defined in an assembly that is not referenced. You must add a reference to assembly 'ProjectC, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.

when I do not have A referencing C.

To clarify I want project A to reference B that uses things from C without A referencing C.

Is this possible?

Answer 1

You won't be able to avoid referencing C, because CBaseClass is part of the public interface of BInheritingClass . Project A has no way of knowing the full definition of BInheritingClass without knowing CBaseClass .

If you want to avoid this, you have to avoid inheritance and use composition - make BInheritedClass not inherit CBaseClass , and instead contain it internally, not exposing it as a parameter or public member. Only that way can it remain an implementation detail of B, not part of its contract.

Answer 2

If project A in any way uses anything defined public in project C , you need to reference C . In your example, project A defines a class based on something defined in C, so you need to reference C.

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You updated your question
This answer is still true: As B defines a BInheritingClass based on CBaseClass defined in C , A needs to know C if it wants to use the class in B , otherwise it would not know the "base features" of CBaseClass and thus can not determine the features of BInheritingClass .

If you don't want A to "know" C , you may not expose anything from C through B to A . Composition is one solution to the problem, but this essentially means you need to remodel the public interface of CBaseClass in BNoLongerInheritingClass .

Answer 3

No, you can't use a class defined in an assembly you did not reference. (Except for dynamic loading with reflection). Maintaining this reference hierarchy is exactly why tools like NuGet where developed.