C# Academy · Lesson

Enums & [Flags]

Define enums with explicit values and underlying types, convert and parse safely, and model combinable options with [Flags].

Enums & [Flags] is a free C# Academy lesson on CoddyKit — lesson 3 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.

Enums overview

Goal: Use enums for named constants and [Flags] for combinable options.

Names map to numbers
Underlying type (int by default)
Cast, parse, and validate
Bitwise combine with [Flags]

Basic enum

Enums are named constants. You can print the name or cast to the underlying number.

using System;

public enum OrderStatus
{
  Pending = 0,
  Processing = 1,
  Shipped = 2,
  Delivered = 3,
  Cancelled = 4
}

public class Program
{
  public static void Main(string[] args)
  {
    OrderStatus s = OrderStatus.Processing;
    Console.WriteLine("Status = " + s);
    Console.WriteLine("Numeric = " + (int)s);
  }
}

Underlying type & cast

You may pick an underlying type (short, byte, etc.). Casting from numbers does not validate the value.

using System;

// Choose underlying type if needed (default is int)
public enum HttpCode : short
{
  Ok = 200,
  NotFound = 404
}

public class Program
{
  public static void Main(string[] args)
  {
    short code = (short)HttpCode.Ok; // cast to number
    HttpCode fromNum = (HttpCode)404; // cast from number (no validation)
    Console.WriteLine("code=" + code);
    Console.WriteLine("fromNum=" + fromNum);
  }
}

Parsing & validation

Use Enum.TryParse to read from text and Enum.IsDefined to validate numeric values.

using System;

public enum Color
{
  Red = 1, Green = 2, Blue = 3
}

public class Program
{
  public static void Main(string[] args)
  {
    Color c;
    bool ok = Enum.TryParse<Color>("green", true, out c); // ignore case
    Console.WriteLine("Parsed? " + ok + " value=" + c);

    // Validate a numeric value before casting
    int raw = 4;
    bool valid = Enum.IsDefined(typeof(Color), raw);
    Console.WriteLine("Is 4 a defined Color? " + valid);
  }
}

[Flags] in practice

Add [Flags] and assign power-of-two values. Combine with |, test with &, remove with ~ and &.

using System;

[Flags]
public enum FileAccessMode
{
  None  = 0,
  Read  = 1,   // 0001
  Write = 2,   // 0010
  Exec  = 4    // 0100
}

public class Program
{
  public static void Main(string[] args)
  {
    FileAccessMode m = FileAccessMode.Read | FileAccessMode.Write; // combine
    Console.WriteLine("Mode = " + m); // prints "Read, Write"

    // Test a flag (two common patterns)
    bool canWrite = (m & FileAccessMode.Write) != 0;
    Console.WriteLine("Can write? " + canWrite);

    // Remove a flag
    m = m & ~FileAccessMode.Write;
    Console.WriteLine("After remove: " + m);
  }
}

Enum tips

Tips:

Give explicit values; keep them stable.
For [Flags], use powers of two and include a None = 0.
Validate inputs with Enum.TryParse/IsDefined.
Avoid using raw integers in public APIs; prefer enums.

Flags attribute meaning

Quick check: Which attribute lets an enum represent combinable bitwise options like Read | Write?

Recap

Recap: Use enums for clear, type-safe constants. Parse and validate safely. For combinable options, add [Flags] and use bitwise operators to set/test/remove flags.

Frequently asked questions

Is the “Enums & [Flags]” lesson free?

Yes — the full text of “Enums & [Flags]” 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 “Enums & [Flags]”?

Define enums with explicit values and underlying types, convert and parse safely, and model combinable options with [Flags]. 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 3 of 3, so you can start here or from the beginning and move at your own pace.

How long does the “Enums & [Flags]” 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

← Back to C# Academy