Fields, auto-properties, object initializers
Define fields and auto-properties, and create objects with concise object initializers.
Fields, auto-properties, object initializers is a free C# Academy lesson on CoddyKit — lesson 1 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C# Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Class basics overview
Goal: Build simple classes.
- Fields hold raw data
- Auto-properties expose data cleanly
- Object initializers set values at creation
Fields in a class
Fields are variables inside a class. For public data, properties are safer.
using System;
// Fields store raw data inside a class
public class Player
{
public string name; // field (usually prefer properties for public APIs)
public int level;
}
public class Program
{
public static void Main(string[] args)
{
Player p = new Player();
p.name = "Ada";
p.level = 1;
Console.WriteLine("Player " + p.name + " level " + p.level);
}
}
Auto-properties
Auto-properties expose data via get/set without writing a field. You can set simple defaults.
using System;
// Auto-properties generate a hidden backing field
public class Book
{
public string Title { get; set; }
public string Author { get; set; }
public int Pages { get; set; } = 0; // auto-property initializer (C# 6)
}
public class Program
{
public static void Main(string[] args)
{
Book b = new Book();
b.Title = "Clean Code";
b.Author = "Robert C. Martin";
b.Pages = 464;
Console.WriteLine(b.Title + " by " + b.Author + " (" + b.Pages + " pages)");
}
}
Object initializers
Object initializers set properties at creation time, keeping code short and clear.
using System;
public class Person
{
public string Name { get; set; }
public int Age { get; set; }
}
public class Program
{
public static void Main(string[] args)
{
// Object initializer calls set-accessors after construction
Person p = new Person { Name = "Alan", Age = 30 };
Console.WriteLine(p.Name + " (" + p.Age + ")");
}
}
Fields vs properties
Guideline:
- Use private fields for internal storage.
- Expose public properties so you can add validation later without breaking callers.
- Keep names clear and simple.
Fields + properties together
Combine a private field with a property to control writes (simple invariants).
using System;
// Private fields + public properties pattern
public class Product
{
private int _stock; // field (internal storage)
public string Name { get; set; } // property (public API)
public int Stock // property with simple guard
{
get { return _stock; }
set
{
if (value < 0) value = 0; // simple safety for beginners
_stock = value;
}
}
}
public class Program
{
public static void Main(string[] args)
{
Product p = new Product { Name = "Pen", Stock = 5 };
p.Stock = -3; // setter clamps to 0
Console.WriteLine(p.Name + " stock = " + p.Stock);
}
}
Auto-property concept
Recap
Recap: Define data with fields and expose it via auto-properties. Use object initializers to set values at creation.
Frequently asked questions
Is the “Fields, auto-properties, object initializers” lesson free?
Yes — the full text of “Fields, auto-properties, object initializers” is free to read here on the web, and the C# Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C# Academy course, upgrade to CoddyKit PRO.
What will I learn in “Fields, auto-properties, object initializers”?
Define fields and auto-properties, and create objects with concise object initializers. You practise C# Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start C# Academy?
No prior experience is required. C# Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “Fields, auto-properties, object initializers” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this C# Academy lesson?
Yes. Every C# Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Fields, auto-properties, object initializers
- Constructors, static members
- Encapsulation & invariants