I need to 2 levels of inheritance and abstraction in master-child relationship

Question

Let\'s assume I have a business case I want to use some model to represent a master-child structure. And there will be certain classes to inherit from both the master class and

Answer 1

Generics + potentially non-generic base class for your "with children" type is the standard solution. If you don't need BaseMaster to be assignment-compatible between different types of child nodes you can remove base non-generic class.

Something roughly like following:

public class BaseMaster
{
    public ReadOnlyCollection<BaseChild> Children { get; }
}

public class BaseMaster<T> : BaseMaster where T: BaseChild
{
    public new IEnumerable<T> Children { get
        {
           return base.Children.Cast<T>();
        };
    }
}

Answer 2

You may get somewhere with generics:

public abstract class BaseMaster<TChild> where TCHild : BaseChild
{
    // this probably doesn't have to be 'abstract' anymore
    public abstract ReadOnlyCollection<TChild> Children { get; }
}

public class FirstRealMaster : BaseMaster<FirstRealChild>
{
}

But we don't know enough about the relation between Master and Child classes to be sure.