Question

I have a

public class A<T> where T : IBase
{
    //Does something
}

I need a second class that behaves like a collection of class A

public class B<A<T>> : IEnumerable<A<T>> where T : IBase
{
}

The problem is that I do not want to create classes like

public class B<A<MyCustomObjectP>> : IEnumerable<A<MyCustomObjectP>>
{
}

public class C<A<MyCustomObjectQ>> : IEnumerable<A<MyCustomObjectQ>>
{
}

and so on.. I would like to let the CustomObject be a generic type parameter that implements IBase.

I found that even doing this is illegal:

public class B<T, U> : IEnumerable<T> where T : A<U> where U : IBase
{
}

How could I achieve this type of behaviour, if this is illegal? Is there a better design pattern of sorts that might help?

Answer 1

The IBase constraint is defined on A<T>, so it must be defined again on all generic classes, that want to use A<U> (using U to distinguish from T in A<T> class definition, but it can be called anything). You should be able to do simply:

public class B<T> : IEnumerable<A<T>> where T : IBase { ... }