C# Enumerations Type - Enum

In C#, an enum (or enumeration type) is used to assign constant names to a group of numeric integer values. It makes constant values more readable, for example, WeekDays.Monday is more readable then number 0 when referring to the day in a week.

An enum is defined using the enum keyword, directly inside a namespace, class, or structure. All the constant names can be declared inside the curly brackets and separated by a comma. The following defines an enum for the weekdays.

@*is a value type data type.*@

Example: Define an Enum

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

Above, the WeekDays enum declares members in each line separated by a comma.

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Enum Values

If values are not assigned to enum members, then the compiler will assign integer values to each member starting with zero by default. The first member of an enum will be 0, and the value of each successive enum member is increased by 1.

Example: Default Enum Values

enum WeekDays
{
    Monday,     // 0
    Tuesday,    // 1
    Wednesday,  // 2
    Thursday,   // 3
    Friday,     // 4
    Saturday,   // 5
    Sunday      // 6
}

You can assign different values to enum member. A change in the default value of an enum member will automatically assign incremental values to the other members sequentially.

Example: Assign Values to Enum Members

enum Categories
{
    Electronics,    // 0
    Food,           // 1
    Automotive = 6, // 6
    Arts,           // 7
    BeautyCare,     // 8
    Fashion         // 9
}

You can even assign different values to each member.

Example: Assign Values to Enum Members

enum Categories
{
    Electronics = 1,  
    Food = 5, 
    Automotive = 6, 
    Arts = 10, 
    BeautyCare = 11, 
    Fashion = 15,
    WomanFashion = 15
}

The enum can be of any numeric data type such as byte, sbyte, short, ushort, int, uint, long, or ulong. However, an enum cannot be a string type.

Specify the type after enum name as : type. The following defines the byte enum.

Example: byte Enum

enum Categories: byte
{
    Electronics = 1,  
    Food = 5, 
    Automotive = 6, 
    Arts = 10, 
    BeautyCare = 11, 
    Fashion = 15
}

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Access an Enum

An enum can be accessed using the dot syntax: enum.member

Example: Access Enum

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

Console.WriteLine(WeekDays.Monday); // Monday
Console.WriteLine(WeekDays.Tuesday); // Tuesday
Console.WriteLine(WeekDays.Wednesday); // Wednesday
Console.WriteLine(WeekDays.Thursday); // Thursday
Console.WriteLine(WeekDays.Friday); // Friday
Console.WriteLine(WeekDays.Saturday); // Saturday
Console.WriteLine(WeekDays.Sunday); // Sunday

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Conversion

Explicit casting is required to convert from an enum type to its underlying integral type.

Example: Enum Conversion

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

Console.WriteLine(WeekDays.Friday); //output: Friday 
int day = (int) WeekDays.Friday; // enum to int conversion
Console.WriteLine(day); //output: 4 
		
var wd = (WeekDays) 5; // int to enum conversion
Console.WriteLine(wd);//output: Saturday

enum is an abstract class. Learn more about enum class members here.