Abstraction in .NET

📘 Table of Contents

• Introduction
• Real-Life Analogy
• Abstract Classes
• Interfaces
• Benefits of Abstraction
• Real-World Example: Payments
• Conclusion

🔍 Introduction

In .NET — and object-oriented programming in general — abstraction is a powerful concept that helps developers write cleaner, more manageable, and scalable code.

At its core, abstraction means hiding internal complexity and exposing only essential features — like showing a simplified interface to a complex system.

🚗 Real-Life Analogy: Teaching Someone to Drive

Imagine teaching someone to drive. You don’t explain combustion, pistons, or gear ratios. You show them:

• The steering wheel
• The gas and brake pedals
• The gear shift

This is abstraction: interacting with essential features, not internal mechanics.

🧱 Abstract Classes in .NET

An abstract class serves as a blueprint. It can include both abstract methods (no body) and concrete methods (with implementation).

Features:

• Cannot be instantiated
• Can contain both abstract and concrete members

abstract class Shape {
    public abstract double GetArea(); // Abstract method
    public void Display() => Console.WriteLine("Displaying shape"); // Concrete method
}

class Circle : Shape {
    public double Radius { get; set; }
    public override double GetArea() => Math.PI * Radius * Radius;
}

🧾 Interfaces: Defining Contracts

An interface defines a contract — what an object must do, not how. Classes that implement the interface must define the logic.

Features:

• All methods are abstract
• Classes can implement multiple interfaces

interface IShape {
    double GetArea();
}

class Rectangle : IShape {
    public double Width { get; set; }
    public double Height { get; set; }
    public double GetArea() => Width * Height;
}

🎯 Why Abstraction Matters

• Reduces complexity: Hide details, focus on use
• Improves maintainability: Change internal logic safely
• Promotes loose coupling: Code depends on contracts, not implementations
• Increases flexibility: Add new types easily without breaking code

💳 Real-World Scenario: Payments in an E-Commerce App

Define an interface:

interface IPaymentMethod {
    void ProcessPayment(decimal amount);
}

Implement different methods:

class CreditCardPayment : IPaymentMethod {
    public void ProcessPayment(decimal amount) {
        Console.WriteLine($"Paid {amount} using Credit Card.");
    }
}

class UpiPayment : IPaymentMethod {
    public void ProcessPayment(decimal amount) {
        Console.WriteLine($"Paid {amount} using UPI.");
    }
}

The system can now handle all payment types via the common IPaymentMethod interface without changing the billing logic.

🧠 Conclusion: Build Smarter with Abstraction

Abstraction is a core part of object-oriented design in .NET. With abstract classes and interfaces:

• You simplify your code
• Improve maintainability
• Support scalability

Always ask: "What does the outside world need to know? What can I hide?"
Mastering abstraction helps you write code that speaks your language — not the machine’s.