Design Patterns

Design Patterns

Design patterns are recurring solutions to software design problems you find again and again in real-world application development. Patterns are about design and interaction of objects, as well as providing a communication platform concerning elegant, reusable solutions to commonly encountered programming challenges.

The Gang of Four (GoF) patterns are generally considered the foundation for all other patterns. They are categorized in three groups: Creational, Structural, and Behavioral. Here you will find information on these important patterns.

To give you a head start, the C# source code is provided in 2 forms: 'structural' and 'real-world'. Structural code uses type names as defined in the pattern definition and UML diagrams. Real-world code provides real-world programming situations where you may use these patterns.

A third form, '.NET optimized' demonstrates design patterns that exploit built-in .NET 4.0 features, such as, generics, attributes, delegates, object and collection initializers, automatic properties, and reflection. These and much more are available in our Design Pattern Framework 4.0TM. See our Singleton page for a .NET 4.0 Optimized code sample.

  Creational Patterns

  Abstract Factory:              Creates an instance of several families of classes

  Builder               :                Separates object construction from its representation

  Factory Method:              Creates an instance of several derived classes

  Prototype:          A fully initialized instance to be copied or cloned

  Singleton:           A class of which only a single instance can exist

  Structural Patterns

  Adapter:              Match interfaces of different classes

  Bridge:                 Separates an object’s interface from its implementation

  Composite:        A tree structure of simple and composite objects

  Decorator:          Add responsibilities to objects dynamically

  Façade:                A single class that represents an entire subsystem

  Flyweight:          A fine-grained instance used for efficient sharing

  Proxy:   An object representing another object

  Behavioral Patterns

  Chain of Resp:.                 A way of passing a request between a chain of objects

  Command:          Encapsulate a command request as an object

  Interpreter:        A way to include language elements in a program

  Iterator:               Sequentially access the elements of a collection

  Mediator:           Defines simplified communication between classes

  Memento:          Capture and restore an object's internal state

  Observer:            A way of notifying change to a number of classes

  State   : Alter an object's behavior when its state changes

  Strategy:              Encapsulates an algorithm inside a class

  Template Method:         Defer the exact steps of an algorithm to a subclass

  Visitor                : Defines a new operation to a class without change