In .Net framework the collections namespace includes classes that represent collection of objects that include lists, queues, bit arrays, hash tables and dictionaries.
System.Collections.Generic is the generic version of
System.Collection namespace. Using it, you can define strongly typed collections while gaining all benefits of generics (code reusability, type safety and better performance).
Let’s take the most commonly used Collection type which is the
List. I will not be explaining about Collections now because it is outside the scope of this article.
So with generics, the List will have its parameter
T, that you can pass to it whatever type you like and you will have a list of that type.