Describing design patterns and with details enough about Singleton Design pattern in C#

1. Amr Fathy

2.  Introduction to design patterns
 What is a singleton design pattern
 Dissecting the classic singleton pattern implementation
 Dealing with Multithreading

3.  A description of an object-oriented
design technique which names, abstracts
and identifies aspects of a design structure that ar
e useful for creating an object
oriented design. The design pattern identifies class
es and instances,
their roles, collaborations and responsibilities. Eac
h design pattern focuses on a particular object-
oriented design problem or issue. It describes when
it
applies, whether it can be applied in the presence o
f other design
constraints, and the consequences and trade-
offs of its use.

4.  The singleton pattern ensures a class has only one instance and
provides a global point access to it .
Look at this
diagram 

6.  We obviously ensure that the singleton works in the presence of multithreads .
Has two status
Lock
unlock

7. Amr Fathy