It is a logical group of related classes and interfaces and that can be used by any language targeting the .net framework.
A class is the generic definition of what an object is. A Class describes all the attributes of the object, as well as the methods that implement the behavior of the member object. In other words, class is a template of an object.
An object is an instance of a class. It contains real values instead of variables.
Dispose method are used for forcefully garbage collection to relase Unmannaged code