Encapsulation, Access Modifiers & Records Masterclass

⚡ C# 12 & .NET 8 🟢 Chapter 16 of 35 📂 Phase 6: Methods & OOP 📅 2026 Edition

📌 Covered in this chapter: Encapsulation · Access Modifiers (public/private/protected/internal) · Property Validation · Immutable Objects · Record Types · Value Equality

Welcome to Phase 6 (Chapter 16): C# Encapsulation, Access Modifiers & Records Masterclass! Encapsulation hides internal implementation details and protects state from unauthorized external modification. In this lesson, we cover access modifiers (public, private, protected, internal), property validation, immutable objects, and C# 9+ Record types.

1Access Modifiers & Encapsulation

Access modifiers restrict the visibility of class members across projects and assemblies:

Modifier	Accessibility Scope
`public`	Accessible from any code anywhere in any project
`private`	Accessible ONLY inside the defining class or struct
`protected`	Accessible inside the defining class AND derived child classes
`internal`	Accessible from any code within the SAME assembly (.dll / .exe)

C# — Encapsulation & Property Validation ▶ Run in Compiler

class BankAccount
{
    private decimal balance; // Hidden private field

    public decimal Balance
    {
        get => balance;
        private set => balance = value; // Private setter
    }

    public void Deposit(decimal amount)
    {
        if (amount <= 0)
            throw new ArgumentException("Deposit amount must be positive!");
        balance += amount;
    }
}

BankAccount acc = new BankAccount();
acc.Deposit(500);
Console.WriteLine($"Account Balance: {acc.Balance:C}");

2C# 9+ Record Types

Records are immutable reference types that automatically generate value-based equality methods, positional constructors, and support non-destructive mutation via the with expression:

C# — Record Types ▶ Run in Compiler

// Record: Immutable reference type with built-in value equality!
public record Person(string FirstName, string LastName, int Age);

Person p1 = new("Ravi", "Kumar", 21);
Person p2 = new("Ravi", "Kumar", 21);

Console.WriteLine($"p1 == p2: {p1 == p2}"); // True (Value equality!)

Person p3 = p1 with { Age = 22 }; // Non-destructive mutation
Console.WriteLine($"p3: {p3}");

3Technical FAQs

Q1: What is the main difference between a class and a record in C#?

Classes use reference-based equality (two instances are equal only if they refer to the same object in memory). Records use value-based equality and provide built-in immutability features.