C# Enumeration

Enumeration is a data type which contains an sequence of names written are inside the body of the enum separated by comma. The names in the sequence have integral values. if the values are not assigned to the names of the enum datatype then the first name has value =0 and second name in sequence has value=1 and so on. But we can assign any arbitrary numeric values to the names as well. For example, enum Month {jan, feb, march, april} 

or, enum Month : int{jan=1, feb=2, march=3, april=4} 

Syntax

enum EnumName : EnumDataType { value1, value2, ...valueN }

or

enum EnumName : EnumDataType { value1=number1, value2=number2, ... valueN=numberN}

Example1 based on enum EnumName : EnumDataType { value1, value2, ...valueN }

using System;

namespace Console_Enum

{

    class Program

    {

        //declare enum datatype

        enum Direction

        {

            North,

            East,

            West,

            South

        }

        static void Main(string[] args)

        {

            //declare enum datatype variable

            Direction north = Direction.North;

            Console.WriteLine("{0}", north);

            Console.WriteLine("Enum.GetNames(typeof(Direction))");

            foreach (var item in Enum.GetNames(typeof(Direction)))

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("Enum.GetValues(typeof(Direction))");

            foreach (var item in Enum.GetValues(typeof(Direction)))

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("Count Values of enum: {0}",Enum.GetNames(typeof(Direction)).Length);

        }

    }

}

OUTPUT

North

Enum.GetNames(typeof(Direction))

North

East

West

South

Enum.GetValues(typeof(Direction))

North

East

West

South

Count Values of enum: 4

Example2 based on enum EnumName : EnumDataType { value1=number1, value2=number2, ... valueN=numberN}

using System;

namespace Console_Enum

{

    class Program

    {

        //declare enum datatype

        enum Direction

        {

            North=3,

            East=1,

            West=2,

            South=4

        }

        static void Main(string[] args)

        {

            //declare enum datatype variable

            Direction north = Direction.North;

            Console.WriteLine("{0}", north);

            Console.WriteLine("Enum.GetNames(typeof(Direction))");

            foreach (var item in Enum.GetNames(typeof(Direction)))

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("Enum.GetValues(typeof(Direction))");

            foreach (var item in Enum.GetValues(typeof(Direction)))

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("Count Values of enum: {0}",Enum.GetNames(typeof(Direction)).Length);

            //Acccess name based on the value

            Console.Write("Acccess name based on the value: ");

            Console.WriteLine(Enum.GetName(typeof(Direction),2));

            

        }

    }

}

OUTPUT

North

Enum.GetNames(typeof(Direction))

East

West

North

South

Enum.GetValues(typeof(Direction))

East

West

North

South

Count Values of enum: 4

Acccess name based on the value: West

Example3

using System;

namespace Console_Enum

{

    class Program

    {

        //declare your enum with its values datatype

        enum Direction: byte

        {

            North=3,

            East=1,

            West=2,

            South=4

        }

        static void Main(string[] args)

        {

            //declare enum datatype variable

            //dirVar is a variable of enum type named Direction 

            Direction dirVar = Direction.North;

            Console.WriteLine("{0}", dirVar);

            dirVar = Direction.South;

            Console.WriteLine("{0}", dirVar);

            //typecast to get the value 

            Console.WriteLine("{0}", (byte)dirVar);

            //get the array of the names of the constants in the Enum

            Console.WriteLine("=====");

            for (int i = 0; i < Enum.GetNames(typeof(Direction)).Length; i++)

            {

                Console.WriteLine(Enum.GetName(typeof(Direction),i+1));

            }

            Console.WriteLine("****Get array of names of enum ******");

            var arr = Enum.GetNames(typeof(Direction));

            foreach (var item in arr)

            {

                Console.WriteLine(item);

            }

            Console.WriteLine("### Given a sequence number of enum, get its Name ####");

            for (int i = 1; i <= Enum.GetNames(typeof(Direction)).Length; i++)

            {

                Console.WriteLine((Direction)i);

            }

            Console.WriteLine("+++++++++++++");

            foreach (var item in arr)

            {

                //parse string of enum

                //here Enum.Parse is used to parse string name of the Direction enum

                //depending upon the typecast the value is returned

                var enumValue = (byte)Enum.Parse(typeof(Direction), item);

                Console.WriteLine(item +" "+ enumValue);

            }

        }

    }

}

OUTPUT:

North

South

4

=====

East

West

North

South

****Get array of names of enum ******

East

West

North

South

### Given a sequence number of enum, get its Name ####

East

West

North

South

+++++++++++++

East 1

West 2

North 3

South 4

Example

using System;

namespace ConsoleApp3

{

    public enum Color { red, green, blue, pink } // by default int

    public enum direction : byte { east, west, north, south }

    public enum quality : byte { good=1, better=2, best=4, excellent=8 }

    public enum width { narrow=2, medium, large}

    //enum typecast to get its numeric values

    class Program

    {

        static void Main(string[] args)

        {

            //enumerate values

            foreach (Color item in Enum.GetValues(typeof(Color)))

            {

                //Console.Write((int)item + " ");//0 1 2 3

                Console.Write(item + " ");//red green blue pink

            }

            Console.WriteLine();

            foreach (var item in typeof(direction).GetEnumValues() )

            {

                Console.Write(item + " ");//east west north south

            }

            Console.WriteLine();

            foreach (var item in typeof(quality).GetEnumNames())

            {

                var result =(byte) Enum.Parse(typeof(quality), item);

                Console.Write(result.ToString() + " "); //1 2 4 8

            }

            Console.WriteLine();

            //Increment by 1 from the initial value

            foreach (var item in typeof(width).GetEnumNames())

            {

                var result = (int)Enum.Parse(typeof(width), item);

                Console.Write(result.ToString() + " "); //2 3 4

            }

            Console.ReadKey();

        }

    }

}

Example

using System;

namespace ConsoleApp3

{

    public enum Color { red=2, green, blue, pink } // by default int

    class Program

    {

        static void Main(string[] args)

        {

            //enumerate names as string array

            Type myEnumtype = typeof(Color);

            string[] enumNames = myEnumtype.GetEnumNames();

            foreach (string item in enumNames)

            {

                Console.WriteLine(item);

            }

            // IsEnumDefined()

            for (int i = 0; i < typeof(Color).GetEnumNames().Length+2; i++)

            {

                Console.WriteLine(myEnumtype.IsEnumDefined(i).ToString()); 

            }

        }

    }

}