When is it Appropriate to use Generics Versus Inheritance?

Question

What are the situations and their associated benefits of using Generics over Inheritance and vice-versa, and how should they be best combined?

Thanks for the answer

Answer 1

Generics and inheritance are two separate things. Inheritance is an OOP concept and generics are a CLR feature that allows you specify type parameters at compile-time for types that expose them.

Inheritance and generics actually work quite well together.

Inheritance:

Inheritance allows me to create one type:

class Pen { }

and then later create another type that extends Pen:

class FountainPen : Pen { }

This is helpful because I can reuse all the state and behavior of the base class and expose any new behavior or state in FountainPen. Inheritance allows me to rapidly create a more specific version of an existing type.

Generics:

Generics are a CLR feature that let me create a type like this:

class Foo<T> 
{
    public T Bar { get; set; }
}

Now when I use Foo<T> I can specify what the type of T will be by providing a generic type argument:

Foo<int> foo = new Foo<int>();

Now, since I have specified that T shall be an int for the object I have just created, the type of Foo.Bar will also be int since it was declared of type T.