Question

Would it be possible to do something like the following in c#?
Basically TParent and TChildren should be types of the class A but not necessairly have the same types that were passed in. I know this may sound confusing but I want to strongly type the children and parents of a particular object, but at the same time they must be of the same type. Because TParent inherits from A this would imply that it requires type parameters that inherit from A but using potentially different types.

public class A<TParent, TChildren> 
    where TParent : A
    where TControls : A
{
    TParent Parent;
    List<TChildren> Children;
}

or more easily seen here:

public class A<TParent, TChildren>
    where TParent : A<?, ?>
    where TChildren : A<?, ?>
{
    TParent Parent;
    List<TChildren> Children;
}

I hope this isn’t too confusing. Is this at all possible?

Thanks 🙂

Answer 1

No, this isn’t possible. One workaround, however, is to create a subclass of A<TParent, TChild> and enforce that the generic type parameters are of that type:

public interface A
{
   // some properties and methods
}

public class A<TParent, TChild> : A where TParent : A where TChild A
{
   // something else here.  
}