An enumeration type (or enum type) is a value type defined by a set of named constants of the underlying integral numeric type. To define an enumeration type, use the enum keyword and specify the names of enum members:
An enum in C# is declared by the enum keyword followed by the enumeration name and its values within a bracket.
By default, the associated constant values of enum members are of type int; they start with zero and increase by one following the definition text order.
In c#, an enumeration can contain only integral data types such as byte, sbyte, short, ushort, int, uint, long or ulong.
Lets see some examples of enum
enum Season { Spring, Summer, Autumn, Winter }
enum Days { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday };
enum Months { Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec };
enum Colors { Yellow, Orage, Red, Green, Blue, Purple, Black };
You can change the default values of an enumerator by assigning a new value to the first item in the enumerator which will automatically assign incremental values to the successive items in an enumerator.
Lets see an example
enum Season
{
Spring = 10,
Summer,
Autumn,
Winter
}
If you wanted to change the default integral type of elements in an enumeration from an int to byte, you can do something like this.
enum Season: byte
{
Spring,
Summer,
Autumn,
Winter
}
Lets see an example
Example 1
Pretty basic example
using System;
public class Program
{
enum Season
{
Spring,
Summer,
Autumn,
Winter
}
public static void Main()
{
int a = (int)Season.Spring;
int b = (int)Season.Autumn;
Console.WriteLine(Season.Spring);
Console.WriteLine(Season.Autumn);
Console.WriteLine("Spring: {0}", a);
Console.WriteLine("Autumn: {0}", b);
Console.WriteLine("\nPress Enter Key to Exit..");
Console.ReadLine();
}
}
Run this and you should see the following
Spring Autumn Spring: 0 Autumn: 2 Press Enter Key to Exit..
Looping an enum
The GetValues method of System.Enum can be used to loop through an enum values and the GetNames method of System.Enum returns a string value of each elements of an enum.
using System;
public class Program
{
enum Season
{
Spring,
Summer,
Autumn,
Winter
}
public static void Main()
{
Console.WriteLine("Read values of the Season enum");
foreach (int i in Enum.GetValues(typeof(Season)))
Console.WriteLine(i);
Console.WriteLine("Read names of the Season enum");
foreach (string str in Enum.GetNames(typeof(Season)))
Console.WriteLine(str);
Console.WriteLine("\nPress Enter Key to Exit..");
Console.ReadLine();
}
}
Run this and you should see as follows
Read values of the Season enum 0 1 2 3 Read names of the Season enum Spring Summer Autumn Winter Press Enter Key to Exit..
enum to a list
You can convert the values of an enum into a List object.
Here is an example of this
using System;
using System.Collections.Generic;
public class Program
{
enum Season
{
Spring,
Summer,
Autumn,
Winter
}
public static void Main()
{
List<string> seasonsList = new List<string>(Enum.GetNames(typeof(Season)));
foreach (string season in seasonsList)
Console.WriteLine(season);
Console.ReadLine();
}
}
enum to array
You can converts enum values into an array. Here is an example.
using System;
using System.Collections.Generic;
public class Program
{
enum Season
{
Spring,
Summer,
Autumn,
Winter
}
public static void Main()
{
string[] seasons = Enum.GetNames(typeof(Season));
foreach (string season in seasons)
Console.WriteLine(season);
Console.ReadLine();
}
}
C# Enum Methods
In c#, we have a class called Enum that contains the following methods to work with an enumeration.
| Method | Description |
|---|---|
| Format | convert the value of enum type to a specified string format. |
| GetName | get the name of the specified enum item. |
| GetNames | get all item names of the specified enum as an array. |
| GetValues | get all item values of the specified enum as an array. |
| Parse | convert the string representation of the name or numeric value of one or more enumerated constants to an equivalent enumerated object. |
| GetUnderlyingType | return the underlying type of the specified enumeration. |