Tutorial: Common Design Patterns in C# 4.0

Design Patterns provide standardized and efficient solutions to software design and programming problems that are re-usable in your code. Software Architects and developers use them to build high quality robust applications.

However, you have to take care to select the right pattern for the right problem. If you need to modify the initial pattern too much, this may indicate that it is not adapted to your needs and may in the worst case lead to unmaintainable, complex and inefficient code. The opposite of what you intend when using Design Patterns !!

You may also create your own custom Design Patterns. Whenever you come up with a certain solution that is reusable in a vast majority of your projects, you may decide to abstract a design pattern out of it. Then you may create your own library of patterns and share them within your whole company, thus creating standards and ameliorating maintainability.

I am going to show you how to use the well known Gang of Four (GoF) Design Patterns in C# 4.0 code. Those patterns will work well in any project that uses C# but especially in WPF, WCF, WinForms, ASP.NET projects.

The GoF Design Patterns are divided into 3 categories : Creational Patterns, Structural Patterns and Behavioral Patterns. I am going to explain each GoF Design Pattern in detail and will show you examples of how to write good C# 4.0 code that implement those patterns.

Creational Patterns

Abstract Factory Pattern: Create instances of classes belonging to different families
Builder Pattern: Separate representation and object construction
Factory Method Pattern: Create instances of derived classes
Prototype Pattern: Clone or copy initialized instances
Singleton Pattern: Class with only one single possible instance

Structural Patterns

Adapter Pattern: Match interfaces of classes with different interfaces
Bridge Pattern:: Separate implementation and object interfaces
Composite: Simple and composite objects tree
Decorator: Dynamically add responsibilities to objects
Facade: Class that represents subclasses and subsystems
Flyweight: Minimize memory usage by sharing as much data as possible with similar objects
Proxy: Object that represents another object

Behavioral Patterns

Chain of Responsibility: Pass requests between command and processing objects within a chain of objects
Command: Encapsulate a method call as an object containing all necessary information
Interpreter: Include language elements and evaluate sentences in a given language
Iterator: Give sequential access to elements in a collection
Mediator: Encapsulates and simplifies communication between objects
Memento: Undo modifications and restore an object to its initial state
Observer: Notify dependent objects of state changes
State: Change object behavior depending on its state
Strategy: Encapsulate algorithms within a class and make them interchangeable
Template Method: Define an algorithm skeleton and delegate algorithm steps to subclasses so that they may be overridden
Visitor: Add new operations to classes without modifying them

There are also many other types of patterns such as: Parallel Patterns, SOA Patterns, Enterprise Architecture Patterns, etc… So if you work in the respective area don’t hesitate to look up patterns that may help you to be more efficient and build better applications.

Reference: https://csharpdesignpatterns.codeplex.com/

Hi.

Design Patterns are "popular solutions for common design problems". Basically there are 3 categories of Design Pattern.

1/Creational

2/Structural

3/Behavioural

and each category contains number of Design patterns.

Without writing the same code again and again we can use Design pattern.

Basically dp are used in almost all projects and it will be better to use and the performance issue also decrease.

Let me give an example of Observer DP.

i have and company and when i will launch a new product then by Observer DP i will send the mail to each client bcoz they are observing me.

Please read it DP and i can assure you that you are really inspired to implement in your project.

Please follow this article and also so many articles are present,

http://www.c-sharpcorner.com/article/design-patterns-in-c-sharp/

let me know if you need any kind of help.

thanks.

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

Guest User9y ago
Design Patterns
https://msdn.microsoft.com/en-us/library/orm-9780596527730-01.aspx
Bikesh Srivastava9y ago
According my theory ,"Design pattern is just a way to write code in c#.",Everyone is using design patter in your application by default ,but they don't know what is this.
So its just way "what scenario you are following to write code in c# using OOPS concept".
Ananth G9y ago
Tutorial: Common Design Patterns in C# 4.0

Design Patterns provide standardized and efficient solutions to software design and programming problems that are re-usable in your code. Software Architects and developers use them to build high quality robust applications.

However, you have to take care to select the right pattern for the right problem. If you need to modify the initial pattern too much, this may indicate that it is not adapted to your needs and may in the worst case lead to unmaintainable, complex and inefficient code. The opposite of what you intend when using Design Patterns !!

You may also create your own custom Design Patterns. Whenever you come up with a certain solution that is reusable in a vast majority of your projects, you may decide to abstract a design pattern out of it. Then you may create your own library of patterns and share them within your whole company, thus creating standards and ameliorating maintainability.

I am going to show you how to use the well known Gang of Four (GoF) Design Patterns in C# 4.0 code. Those patterns will work well in any project that uses C# but especially in WPF, WCF, WinForms, ASP.NET projects.

The GoF Design Patterns are divided into 3 categories : Creational Patterns, Structural Patterns and Behavioral Patterns. I am going to explain each GoF Design Pattern in detail and will show you examples of how to write good C# 4.0 code that implement those patterns.
Creational Patterns
- Abstract Factory Pattern: Create instances of classes belonging to different families
- Builder Pattern: Separate representation and object construction
- Factory Method Pattern: Create instances of derived classes
- Prototype Pattern: Clone or copy initialized instances
- Singleton Pattern: Class with only one single possible instance
Structural Patterns
- Adapter Pattern: Match interfaces of classes with different interfaces
- Bridge Pattern:: Separate implementation and object interfaces
- Composite: Simple and composite objects tree
- Decorator: Dynamically add responsibilities to objects
- Facade: Class that represents subclasses and subsystems
- Flyweight: Minimize memory usage by sharing as much data as possible with similar objects
- Proxy: Object that represents another object
Behavioral Patterns
- Chain of Responsibility: Pass requests between command and processing objects within a chain of objects
- Command: Encapsulate a method call as an object containing all necessary information
- Interpreter: Include language elements and evaluate sentences in a given language
- Iterator: Give sequential access to elements in a collection
- Mediator: Encapsulates and simplifies communication between objects
- Memento: Undo modifications and restore an object to its initial state
- Observer: Notify dependent objects of state changes
- State: Change object behavior depending on its state
- Strategy: Encapsulate algorithms within a class and make them interchangeable
- Template Method: Define an algorithm skeleton and delegate algorithm steps to subclasses so that they may be overridden
- Visitor: Add new operations to classes without modifying them
There are also many other types of patterns such as: Parallel Patterns, SOA Patterns, Enterprise Architecture Patterns, etc… So if you work in the respective area don’t hesitate to look up patterns that may help you to be more efficient and build better applications.

Reference: https://csharpdesignpatterns.codeplex.com/
Salman Beg9y ago
Hi.
Design Patterns are "popular solutions for common design problems". Basically there are 3 categories of Design Pattern.
1/Creational
2/Structural
3/Behavioural
and each category contains number of Design patterns.
Without writing the same code again and again we can use Design pattern.
Basically dp are used in almost all projects and it will be better to use and the performance issue also decrease.

Let me give an example of Observer DP.
i have and company and when i will launch a new product then by Observer DP i will send the mail to each client bcoz they are observing me.
Please read it DP and i can assure you that you are really inspired to implement in your project.
Please follow this article and also so many articles are present,
http://www.c-sharpcorner.com/article/design-patterns-in-c-sharp/
let me know if you need any kind of help.
thanks.
Ravi Patel9y ago
Hi

check this

https://csharpdesignpatterns.codeplex.com/

https://www.youtube.com/watch?v=YDobmucohqk

What are Design Patterns?

Design Patterns

Tutorial: Common Design Patterns in C# 4.0

Creational Patterns

Structural Patterns

Behavioral Patterns