Question

Assuming I have a class like this:

class Base { }
class A : Base { }
class B : Base { }
class C : Base { }

And objects like this:

A a = new A();
List<B> bs = new List<B>();
List<C> cs = new List<C>();

Is it possible to create a new list containing references to the other lists (So that changes are reflected in the original items?
Such as:

void modifyContents(List<Base> allItems) {
  //modify them somehow where allItems contains a, bs and cs
}

Answer 1

You can not add/remove/replace items in the other lists, but modify the items in the other lists.

List<Base> baseList = new List<Base>();
baseList.Add(a);
baseList.AddRange(bs);
baseList.AddRange(cs);
// now you can modify the items in baseList