Design patterns are a fundamental concept in software development, and their correct implementation can lead to more efficient, maintainable, and scalable code.
In this tutorial, you will learn about the SOLID principles and various Creational, Structural, and Behavioral design patterns, and how to implement them in C# applications.
Through real-world examples and best practices, you will gain the skills and knowledge needed to write high-quality code and communicate effectively with other developers.
By the end of this tutorial, you will have the confidence and expertise to tackle complex C# development projects using design patterns and take your skills to the next level.
What you’ll learn in C# Design Patterns:
- Understanding of SOLID principles and practical applications in C# development
- Knowledge of various Creational, Structural, and Behavioral design patterns and when to use them in C# development.
- Best practices for implementing design patterns in C# applications.
- Real-world examples of design patterns in C# applications.
- Improved code quality and maintainability through the use of design patterns.
Section 1. SOLID Principles
SOLID principles are a set of five principles in software development that guide you in creating maintainable and scalable software. These principles provide guidelines for creating software applications that are easy to modify and extend, reducing the risk of introducing bugs and increasing the codebase quality.
- Single Responsibility Principle (SRP) – a class should have only one reason to change, meaning it should only have one responsibility.
- Open/Closed Principle (OCP) – a class should be open for extension but closed for modification, meaning it should be easy to extend the behavior of a class without changing its source code.
- Liskov Substitution Principle (LSP) – subtypes should be substitutable for their base types, meaning that any class that inherits from a base class should be able to be used in place of the base class without causing errors or unexpected behavior.
- Interface Segregation Principle (ISP) – clients should not be forced to depend on interfaces they do not use, meaning that interfaces should be designed to be specific to the needs of each client.
- Dependency Inversion Principle (DIP) – high-level modules should not depend on low-level modules, but both should depend on abstractions, meaning that code should be designed so that modules can be replaced or extended without causing problems for other parts of the system.
Section 2. Creational Patterns
Creational patterns are a type of design pattern in software development that deals with the process of object creation. These patterns provide various ways to create objects, each with its own set of advantages and disadvantages.
- Singleton – ensures a class has only one instance, and provides a global point of access to that instance.
- Factory Method – defines an interface for creating objects, but allows subclasses to decide which classes to instantiate.
- Abstract Factory – provides an interface for creating families of related or dependent objects without specifying their concrete classes.
- Builder – separates the construction of a complex object from its representation, allowing the same construction process to create different representations.
- Prototype – creates new objects by cloning an existing one, rather than creating a new instance from scratch.
Section 3. Structural Patterns
Structural patterns deal with the composition of classes and objects. These structural patterns provide effective ways to combine objects to form larger structures while keeping the individual objects separate and loosely coupled.
- Adapter – converts the interface of a class into another interface clients expect, allowing classes to work together that couldn’t otherwise.
- Bridge – separates an object’s abstraction from its implementation, allowing both to vary independently.
- Composite – treats individual objects and compositions of objects uniformly, allowing them to be used interchangeably.
- Decorator – adds new behavior to an object dynamically, without affecting the behavior of other objects in the same class.
- Facade – provides a simplified interface to a complex system of classes, reducing dependencies and making the system easier to use.
- Flyweight – shares a common state between objects, reducing memory usage and improving performance.
- Proxy – provides a placeholder for another object to control access to it, allowing additional functionality to be provided as needed.
Section 4. Behavioral Patterns
Behavioral patterns deal with the communication and interaction between objects. The behavioral patterns provide effective ways to manage complex object interactions and behaviors, making it easier to modify and extend code.
- Chain of Responsibility – allows you to pass a request to a chain of handlers until a handler can handle the request, without tight coupling between the sender and receiver.
- Command – encapsulates a request as an object, allowing it to be queued, logged, and undone.
- Interpreter – defines a language and its grammar, and implements an interpreter for that language.
- Iterator – defines an interface for iterating elements of an aggregate object without exposing its underlying representation.
- Mediator – defines an object that encapsulates how a set of objects interact, reducing the coupling between them.
- Memento – captures the internal state of an object without exposing its implementation, allowing it to be restored later.
- Observer – defines a one-to-many dependency between objects, so that when one object changes, all its dependents are notified and updated automatically.
- State – allows an object to alter its behavior when its internal state changes, allowing it to appear to change its class.
- Strategy – defines a family of algorithms, encapsulates each one, and makes them interchangeable, allowing the algorithm to vary independently of clients that use it.
- Template Method – defines the skeleton of an algorithm in a base class, allowing subclasses to provide specific implementations of certain steps.
- Visitor – separates an algorithm from an object structure, allowing new operations to be added without modifying the objects themselves.
