What are and how to use enumerations in C#

An enumeration is a user-defined value type consisting of a set of named constants (we will call each element a ‘member’ of the enumeration).

Each member of the enumeration is a constant that represents a unique integer value, starting from 0 by default and increasing by one for each subsequent member.

Defining an enumeration

To define an enumeration in C#, you use the keyword enum followed by the enumeration name and a block containing the enumeration members:

enum DaysOfTheWeek
{
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
}

Enumerations with specific values

It is possible to assign specific values to enumeration members instead of using the default values.

This way, you can start the enumeration at a value other than 0 and assign custom values to each member.

enum WeekDays
{
    Monday = 1,
    Tuesday = 2,
    Wednesday = 3,
    Thursday = 4,
    Friday = 5,
    Saturday = 6,
    Sunday = 7
}

enum WeekDays
{
    Monday = 1,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
}

Using enumerations

DaysOfTheWeek today = DaysOfTheWeek.Monday;

if (today == DaysOfTheWeek.Monday)
{
    Console.WriteLine("Today is Monday.");
}

Converting enumerations

Enumerations in C# are based on integer data types, so it is possible to convert between an enumeration and its underlying type, which is int by default.

int numericValue = (int)DaysOfTheWeek.Wednesday;
Console.WriteLine(numericValue); // Output: 2

DaysOfTheWeek day = (DaysOfTheWeek)4;
Console.WriteLine(day); // Output: Friday

Iterating over enumeration values

Sometimes, it can be useful to iterate over the values of an enumeration. To do this, you can use the static method Enum.GetValues() which returns an array with all the values of the enumeration. Here is an example:

foreach (MonthsOfYear month in Enum.GetValues(typeof(MonthsOfYear)))
{
   Console.WriteLine(month);
}

Practical examples

enum TaskStatus
{
    Pending,
    InProgress,
    Completed,
    Canceled
}

class Task
{
    public string Name { get; set; }
    public TaskStatus Status { get; set; }

    public void ShowStatus()
    {
        Console.WriteLine($"The task '{Name}' is in status: {Status}");
    }
}

class Program
{
    static void Main()
    {
        Task task = new Task
        {
            Name = "Study for the exam",
            Status = TaskStatus.InProgress
        };

        task.ShowStatus(); // Output: The task 'Study for the exam' is in status: InProgress
    }
}

enum EnemyType
{
    Goblin,
    Orc,
    Dragon
}

class Enemy
{
    public EnemyType Type { get; set; }

    public void ShowType()
    {
        Console.WriteLine($"This enemy is a: {Type}");
    }
}

class Program
{
    static void Main()
    {
        Enemy enemy = new Enemy
        {
            Type = EnemyType.Dragon
        };

        enemy.ShowType(); // Output: This enemy is a: Dragon
    }
}