Design Patterns in C# .NET: A Comprehensive Guide
Asharib Kamal
Sr. Full Stack Developer | Specializing in .NET Technologies | C# | Dot NET Core | Asp.NET MVC | Angular | SQL | Content Creator | Transforming Ideas into High-Impact Web Solutions | 6K + Followers
Introduction:
Design patterns play a crucial role in software development, providing reusable solutions to common problems encountered during the design and implementation of software systems. In this article, we'll explore the fundamental design patterns in C .NET, including their definitions, code examples, pros and cons, benefits, and practical scenarios for their usage.
Creational Design Patterns:
1. Singleton Pattern: Ensures that a class has only one instance and provides a global point of access to it.
- Pros: Simple implementation, lazy initialization.
- Cons: Potential thread-safety issues.
- Example: Logging systems, database connection managers.
2. Factory Method Pattern: Defines an interface for creating an object but allows subclasses to alter the type of objects that will be created.
- Pros: Decouples object creation from object usage.
- Cons: Increased complexity due to the introduction of multiple factories.
- Example: Creating different types of vehicles in a transportation system.
3. Abstract Factory Pattern: Provides an interface for creating families of related or dependent objects without specifying their concrete classes.
- Pros: Supports creating families of related objects.
- Cons: Increased complexity, rigid structure.
- Example: Creating GUI components for different operating systems.
Structural Design Patterns:
1. Adapter Pattern: Allows incompatible interfaces to work together by converting the interface of one class into another interface clients expect.
- Pros: Promotes code reusability and flexibility.
- Cons: Increases the number of objects in the system.
- Example: Adapting third-party libraries to fit into your application's architecture.
2. Decorator Pattern: Attaches additional responsibilities to an object dynamically, providing a flexible alternative to subclassing for extending functionality.
- Pros: Supports adding new functionality without altering existing code.
- Cons: Can lead to a complex hierarchy of decorators.
- Example: Adding behaviors to a component in a UI framework.
3. Composite Pattern: Composes objects into tree structures to represent part-whole hierarchies, allowing clients to treat individual objects and compositions uniformly.
- Pros: Simplifies the client code, enables treating objects uniformly.
- Cons: May not be suitable for systems with dynamic structure changes.
- Example: Representing hierarchical structures like organization charts.
Behavioral Design Patterns:
1. Observer Pattern: Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
- Pros: Promotes loose coupling between objects.
- Cons: Overuse may lead to performance issues.
- Example: Implementing event handling mechanisms in GUI frameworks.
2. Strategy Pattern: Defines a family of algorithms, encapsulates each one, and makes them interchangeable, allowing clients to use different algorithms dynamically.
- Pros: Promotes code reuse and flexibility.
- Cons: Increases the number of classes in the system.
- Example: Implementing different sorting algorithms in a sorting library.
3. Command Pattern: Encapsulates a request as an object, thereby allowing for parameterization of clients with queues, requests, and operations.
- Pros: Decouples the sender and receiver of a request.
- Cons: May lead to the proliferation of command classes.
- Example: Implementing undo/redo functionality in text editors.
1. Singleton Pattern:
public class Singleton
{
private static Singleton instance;
private Singleton() { }
public static Singleton Instance
{
get
{
if (instance == null)
{
instance = new Singleton();
}
return instance;
}
}
}
2. Factory Method Pattern:
public abstract class Creator
{
public abstract Product FactoryMethod();
}
public class ConcreteCreator : Creator
{
public override Product FactoryMethod()
{
return new ConcreteProduct();
}
}
public abstract class Product { }
public class ConcreteProduct : Product { }
3. Abstract Factory Pattern:
public interface IAbstractFactory
{
IProductA CreateProductA();
IProductB CreateProductB();
}
public interface IProductA { }
public interface IProductB { }
public class ConcreteFactory1 : IAbstractFactory
{
public IProductA CreateProductA()
{
return new ConcreteProductA1();
}
public IProductB CreateProductB()
{
return new ConcreteProductB1();
}
}
public class ConcreteFactory2 : IAbstractFactory
{
public IProductA CreateProductA()
{
return new ConcreteProductA2();
}
public IProductB CreateProductB()
{
return new ConcreteProductB2();
}
}