Classes, Objects, Properties, Constructors, and Encapsulation
Model real entities in C# using classes, object state, methods, properties, constructors, and clean encapsulation.
Inside this chapter
- Defining a Class
- Properties
- Constructors
- Encapsulation and Access Modifiers
- Class Design Advice
- Real-World Usage Snapshot
Series navigation
Study the chapters in order for the clearest path from C# syntax and OOP to modern .NET web development, data access, async programming, architecture, and advanced engineering practice. Use the navigation at the bottom to move smoothly through the full series.
Defining a Class
public class BankAccount
{
public string Owner { get; }
public decimal Balance { get; private set; }
public BankAccount(string owner, decimal initialBalance)
{
Owner = owner;
Balance = initialBalance;
}
public void Deposit(decimal amount)
{
Balance += amount;
}
}Classes combine data and behavior. Properties make state exposure more controlled and idiomatic than using public fields directly.
Properties
Properties are a central part of C# object design. They allow validation, controlled updates, and clean APIs while still looking simple to consumers.
Constructors
Constructors ensure objects start in valid states. Clear constructor design improves correctness and prevents partially initialized objects.
Encapsulation and Access Modifiers
publicexposes members broadlyprivatehides implementation detailsprotectedsupports inheritance scenariosinternallimits visibility to the assembly
Class Design Advice
Keep classes focused, protect invariants, and avoid “god classes” that manage too many responsibilities. Good encapsulation makes systems easier to test and change safely.
Real-World Usage Snapshot
Class-based design appears across DTOs, services, domain models, request handlers, UI models, and infrastructure components. Strong foundational object modeling helps throughout the C# ecosystem.