Design Patterns

I am starting to write articles on design patterns. We have 3 types of design patterns as per GoF. There are plenty of design patterns available but 23 standard pattern I am going to cover in my article. Design patterns are Solutions to commonly occurring design problem. Someone has already faced the problem and come up with good and elegant solution. The same pattern you have to use. Design Pattern divided into 3 categories.

1. Creational
2. Behavioral
3. Structural
   1. Creational
      
      Concerned about ways to create new objects.  
   2. Behavioral
      
      Concerned about ways in which objects interacted  
   3. Strucural
      
      Concerned about the composition of objects and classes

Creational Patterns

Singleton	To Create a sole instance of a class
Prototype	To create object by cloning existing object.
Builder	Build an object from existing representation
Factory Method	Defer instantiation to subclass
Abstract Factory	Provides interface to create families of objects without specifying the concrete classes of the objects

Structural Patterns

Adapter	Convert an instance to another
Composite	Composite objects in a tree structure
Decorator	Attach additional responsibilities dynamically
Proxy	Provide a surrogate or placeholder for another object
Façade	Provide a unified instance to a set of instances in sub system
Bridge	Decouple abstraction from implementation. Let them vary and independent.
Flyweight	A fine-grained instance user for efficient sharing

Behavioral Pattern

Chain of Resp.	Delegates commands to a chain of processing objects.
Command	Creates objects which encapsulate actions and parameters.
Interpreter	Implements a specialized language.
Iterator	Accesses the elements of an object sequentially without exposing its underlying representation.
Mediator	Allows loose coupling between classes by being the only class that has detailed knowledge of their methods.
Memento	Provides the ability to restore an object to its previous state (undo).
Observer	Publish/subscribe pattern which allows a number of observer objects to see an event.
State	Allows an object to alter its behavior when it's internal state changes.
Strategy	Allows one of a family of algorithms to be selected on-the-fly at runtime.
Template Method	Defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.
Visitor	Separates an algorithm from an object structure by moving the hierarchy of methods into one object.

Reference Books

C# 3.0 Design Patterns
Design Patterns in C#

C# 3.0 Design Patterns
Agile Principles, Patterns, and Practices in C#
Pro .NET 4 Parallel Programming in C# (Expert's Voice in .NET)
C# Design Patterns: A Tutorial