C# Enums

In this chapter you will learn:

What
How to use enum type
Example for create an enum type
Print out the details of any enum
How to create enum type
Is enum value defined
How to use enum with switch statement
How to get all names for an enum
How to create enum from string
How to check if a string value is defined

Description

An enum is a special value type that lets you specify a group of named numeric constants.

Syntax

The keyword enum declares an enumerated type. The general form for an enumeration is


enum name { 
    enumeration list 
};

name specifies the enumeration type name. enumeration list is a comma-separated list of identifiers.

Each of the symbols stands for an integer value. Each of the symbols has a value one greater than the symbol that precedes it. By default, the value of the first enumeration symbol is 0.

Example

Example for create an enum type


using System;//from  ww  w  .j av a2s. c  o m

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

class MainClass
{
  static void Main(string[] args)
  {
    DaysOfWeek Today = DaysOfWeek.Monday;

    Console.WriteLine(Today);
  }
}

The code above generates the following result.

Example 2

Print out the details of any enum


using System;//from ww  w.  j  a  v a 2s.  co  m
using System.Collections.Generic;
using System.Text;

enum EmpType : byte
{
  Manager = 10,
  Grunt = 1,
  Contractor = 100,
  VicePresident = 9
}

class Program
{
  static void Main(string[] args)
  {
    EmpType e2 = EmpType.Contractor;
    DayOfWeek day = DayOfWeek.Friday;
    ConsoleColor cc = ConsoleColor.Black;
    EvaluateEnum(e2);
    EvaluateEnum(day);
    EvaluateEnum(cc);
  }
  static void EvaluateEnum(System.Enum e)
  {
    Console.WriteLine("=> Information about {0}", e.GetType().Name);
    Console.WriteLine("Underlying storage type: {0}",Enum.GetUnderlyingType(e.GetType()));
    Array enumData = Enum.GetValues(e.GetType());
    Console.WriteLine("This enum has {0} members.", enumData.Length);
    for (int i = 0; i < enumData.Length; i++)
    {
      Console.WriteLine("Name: {0}, Value: {0:D}", enumData.GetValue(i));
    }
  }
}

The code above generates the following result.

Example 3

We can create enum type from existing enum type.


enum WeekEnd{//w  w  w . j  a  v  a  2 s.c o m
  Saturday, Sunday
}

enum WeekDay{
   Monday, Tuesday, Wednesday, Thursday, Friday, Saturday = WeekEnd.Saturday, Sunday = WeekEnd.Sunday
}

Example 4

Enum has a static method we can use to check if an enum value is defined.


using System;//from  ww w .ja va2 s  . c  om

public enum WeekDay{

   Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday

}

class Test
{
    static void Main()
    {
        WeekDay day = (WeekDay)111;

        if (Enum.IsDefined(day.GetType(),day))
        {
            Console.WriteLine("defined");
        }
        else
        {
            Console.WriteLine("not defined");

        }

    }
}

The output:

Example 5

How to use enum with switch statement


using System;/* w w  w . j av  a 2 s.co  m*/

enum EmployeeType : byte 
{
  Manager = 10,
  Programmer = 1,
  Contractor = 100,
  Developer = 9
}

class MainClass
{
  public static void myFunction(EmployeeType e)
  {
    switch(e)
    {
      case EmployeeType.Contractor:
        Console.WriteLine("EmployeeType.Contractor");
        break;
      case EmployeeType.Programmer:
        Console.WriteLine("EmployeeType.Programmer");
        break;
      case EmployeeType.Manager:
        Console.WriteLine("EmployeeType.Manager");
        break;
      case EmployeeType.Developer:
        Console.WriteLine("EmployeeType.Developer");
        break;
      default: break;
    }
  }
  public static void Main(string[] args)
  {
    
    EmployeeType fred;
    fred = EmployeeType.Developer;
    myFunction(fred);

  }
}

The code above generates the following result.

Example 6

How to get all names for an enum


using System;/*from  w w  w  . j a  v  a2s. c o  m*/

enum Color
{
    red,
    green,
    yellow
}

public class MainClass
{
    public static void Main()
    {
        Color c = Color.red;
        
        foreach (string s in Enum.GetNames(c.GetType()))
        {
            Console.WriteLine("Name: {0}", s);
        }
        
    }
}

The code above generates the following result.

Example 7

How to create enum from string


using System;//from w  ww .j  a  v  a2  s  .c  om

enum Color
{
    red,
    green,
    yellow
}

public class MainClass
{
    public static void Main()
    {
        Color c = Color.red;
        
        // 
        c = (Color) Enum.Parse(typeof(Color), "Red", true);
        Console.WriteLine("string value is: {0}", c);
        
    }
}

The code above generates the following result.

Example 8

How to check if a string value is defined


using System;//ww  w.j av  a 2  s .  co  m

enum EmployeeType : byte 
{
  Manager = 10,
  Programmer = 1,
  Contractor = 100,
  Developer = 9
}

class MainClass
{
  public static void Main(string[] args)
  {
    if(Enum.IsDefined(typeof(EmployeeType), "SalesPerson"))
      Console.WriteLine("Yep, we have sales people.");
    else
      Console.WriteLine("No, we have no profits....");
  }
}

The code above generates the following result.

Next chapter...

What you will learn in the next chapter:

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C# Enums

C# Enum Value
C# Enum Underlying integral value
C# Flag Enum