#1,043 – Deriving from a Self-Referencing Constructed Type, part II

When defining a type, you can derive from a constructed generic type that takes the defining type as its type argument.  This technique allows extending the behavior of some base class, but with the advantages of using generics.

    public class CreaturesParents<T>
    {
        public T Mom { get; set; }
        public T Dad { get; set; }

        public string ParentInfo()
        {
            return string.Format("Mom: {0}, Dad: {1}", Mom.ToString(), Dad.ToString());
        }
    }

    public class Dog : CreaturesParents<Dog>
    {
        public string Name { get; set; }
        public int Age { get; set; }

        public Dog(string name, int age)
        {
            Name = name;
            Age = age;
        }

        public override string ToString()
        {
            return string.Format("{0} is {1} yrs old", Name, Age);
        }
    }

Example of using this type:

            Dog fido = new Dog("Fido", 4);
            Dog lassie = new Dog("Lassie", 12);
            Dog bowser = new Dog("Bowser", 9);

            fido.Mom = lassie;
            fido.Dad = bowser;

            Console.WriteLine(fido.ParentInfo());