.Net framework architecture has divided into 4 types

Diagram for .Net Framework Architecture

Framework Architecture
♦    layer 1 is representing .net supporting languages, they are  VB.net, VC++.net, C#.net

♦    To develop any type of application by using .net , programmer required one .net language.

♦    layer 2 us representing .net supporting technologies, they are Windows Forms, ASP.NET

♦    Using .net if you want to develop a windows application we have to use .net windows technology called  windows forms and we have to use any one of the .net language like C#.net or VB.net

♦    If you want to develop a web application by using .net we have to use a .net web technology called ASP.net and we have to use a .net language called C#.net r VB.net

♦    Layer 3 is representing Base class libraries.

♦    Class is a collection of members.

♦    Classes are two types.

          ♦   Pre Defined Classes
               - A class which is defined by the Microsoft can be called as Predefined class
          ♦   User Defined Classes
               - A class which is defined by the programmer can be called as user defined class.

♦    Class Library is a collection of classes, which are classified in to two types.

         ♦   Base Class Library
              - Base class library is a collection of predefined classes.
             - Microsoft is providing a collection of base class libraries for .net programmers with .net software to reduce the programmer task.
            - Whenever a programmer wants to use particular base class library he has to import with the help of using keyword like below.
Example : using system;

♦   User Defined Class libraries
     - User defined class library is a collection of user defined classes.

♦ Layer 4 is representing common language Runtime (CLR)

♦  CLR is a common execution engine for all .net languages.