Csharp/CSharp Tutorial/Data Type/enum

Assign enum value from a member and variable

using System;
enum Color
{
   Green,
   Yellow,
   Red
}
class MainClass
{
   static void Main()
   {
      Color t1 = Color.Red;     
      Color t2 = Color.Green;   
      Color t3 = t2;                   
      Console.WriteLine(t1);
      Console.WriteLine(t2);
      Console.WriteLine(t3);
   }
}

Red
Green
Green

Assign int value to enumerations

using System;
enum Values
{
    A = 1,
    B = 5,
    C = 3,
    D = 42
}
class MainClass
{
    public static void Main()
    {
        Values v = (Values) 2;
        int ival = (int) v;
    }
}

Declaration of enum data type

using System;
enum DaysOfWeek
{
  Monday,
  Tuesday,
  Wednesday,
  Thursday,
  Friday,
  Saturday,
  Sunday
}
class MainClass
{
  static void Main(string[] args)
  {
    DaysOfWeek Today = DaysOfWeek.Monday;
    Console.WriteLine(Today);
  }
}

Monday

Define constants with const keywords and enum

using System;
enum MyEnum
{
    A
}
class Constants
{
    public const MyEnum value3 = MyEnum.A;
}
class MainClass
{
    public static void Main()
    {
        Console.WriteLine("{0}", Constants.value3);
    }
}

A

Enumerations

1. An enumeration is a set of named integer constants.
2. The keyword enum declares an enumerated type.

The general form for an enumeration is

enum name { 
    enumeration list 
};

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

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

Enumerations Initialization with calculation

using System;
enum Values
{
    A = 1,
    B = 2,
    C = A + B,
    D = A * C + 33
}
class MainClass
{
    public static void Member(Values value)
    {
        Console.WriteLine(value);
    }
    public static void Main()
    {
        Values value = 0;
        Member(value);
    }
}

0

Enumerations Initialization with integer value

enum Values
{
    A = 1,
    B = 5,
    C = 3,
    D = 42
}

Loop through the enum data type

using System; 
 
class MainClass { 
  enum Week { Monday, Tuesday, Wednesday, Thursday, Friday, Saturaday,Sunday }; 
 
  public static void Main() { 
    Week i;
 
    for(i = Week.Monday; i <= Week.Sunday; i++)  
      Console.WriteLine(i + " has value of " + (int)i); 
 
  } 
}

Monday has value of 0
Tuesday has value of 1
Wednesday has value of 2
Thursday has value of 3
Friday has value of 4
Saturaday has value of 5
Sunday has value of 6

Output enum element value

using System;
enum Color
{
    red,
    green,
    yellow
}
public class MainClass
{
    public static void Main()
    {
        Color c = Color.red;
        
        Console.WriteLine("c is {0}", c);
    }
}

c is red

Pass enum data to a method

using System;

public enum LineStyle
{
    Solid,
    Dotted,
    DotDash,
}
    
class MainClass
{
    public static void Main()
    {
        DrawLine(LineStyle.Solid);
        DrawLine((LineStyle) 35);
    }
    public static void DrawLine(LineStyle lineStyle)
    {
        switch (lineStyle)
        {
            case LineStyle.Solid:
                Console.WriteLine("draw solid");
                break;
            
            case LineStyle.Dotted:
                Console.WriteLine("draw dotted");
                break;
            
            case LineStyle.DotDash:
                Console.WriteLine("draw dotdash");
                break;
            
            default:
                throw(new ArgumentException("Invalid line style"));
        }
    }
    
}

draw solid
Unhandled Exception: System.ArgumentException: Invalid line style
   at MainClass.DrawLine(LineStyle lineStyle)
   at MainClass.Main()

Print out the details of any enum

using System;
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));
      }
    }
  }

Readonly Fields with enum

public enum ColorEnum
{
    Red,
    Blue,
    Green
}
class Color
{
    public Color(int red, int green, int blue)
    {
        this.red = red;
        this.green = green;
        this.blue = blue;
    }
    
    public static Color GetPredefinedColor(ColorEnum pre)
    {
        switch (pre)
        {
            case ColorEnum.Red:
               return(new Color(255, 0, 0));
            
            case ColorEnum.Green:
               return(new Color(0, 255, 0));
            
            case ColorEnum.Blue:
               return(new Color(0, 0, 255));
            
            default:
               return(new Color(0, 0, 0));
        }
    }
    int red;
    int blue;
    int green;
}
class MainClass
{
    static void Main()
    {
        Color background = Color.GetPredefinedColor(ColorEnum.Blue);
    }
}

Use an enumeration to index an array

using System; 
 
class MainClass { 
  enum Week { Monday, Tuesday, Wednesday, Thursday, Friday, Saturaday,Sunday }; 
 
  public static void Main() { 
    Week i;
 
    
    for(i = Week.Monday; i <= Week.Sunday; i++)  
      Console.WriteLine("Color of " + i + " is "+ (int)i); 
 
  } 
}

Color of Monday is 0
Color of Tuesday is 1
Color of Wednesday is 2
Color of Thursday is 3
Color of Friday is 4
Color of Saturaday is 5
Color of Sunday is 6

Use enum data as flags

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Runtime.InteropServices;
[Flags]
enum FileAccess
{
    Read = 1,
    Write = 2,
    ReadWrite = 3
}

public class MainClass
{
   public static void Main(){
        FileAccess rw1 = FileAccess.Read | FileAccess.Write;
        Console.WriteLine("rw1 == {0}", rw1);
        FileAccess rw2 = FileAccess.ReadWrite;
        Console.WriteLine("rw2 == {0}", rw2);
        Console.WriteLine("rw1 == rw2? {0}", rw1 == rw2);
        if (rw1 == FileAccess.Read)
            Console.WriteLine("try #1: read permitted");
        else
            Console.WriteLine("try #1: read denied");
        if ((rw2 & FileAccess.Read) != 0)
            Console.WriteLine("try #2: read permitted");
        else
            Console.WriteLine("try #2: read denied");
   }
}

rw1 == ReadWrite
rw2 == ReadWrite
rw1 == rw2? True
try #1: read denied
try #2: read permitted

Use enum type categorize objects

using System;
enum EmployeeTypeEnum
{
    Employee,
    Manager
}
class Employee
{
    public Employee(string name, float billingRate)
    {
        this.name = name;
        this.billingRate = billingRate;
        type = EmployeeTypeEnum.Employee;
    }
    
    public float CalculateCharge(float hours)
    {
        if (type == EmployeeTypeEnum.Manager)
        {
            Manager c = (Manager) this;
            return(c.CalculateCharge(hours));
        }
        else if (type == EmployeeTypeEnum.Employee)    
            return(hours * billingRate);
        return(0F);
    }
    
    public string TypeName()
    {
        if (type == EmployeeTypeEnum.Manager)
        {
            Manager c = (Manager) this;
            return(c.TypeName());
        }
        else if (type == EmployeeTypeEnum.Employee)
            return("Employee");
        return("No Type Matched");
    }
    
    private string name;
    protected float billingRate;
    protected EmployeeTypeEnum type;
}
class Manager: Employee
{
    public Manager(string name, float billingRate) :
    base(name, billingRate)
    {
        type = EmployeeTypeEnum.Manager;
    }
    
    public new float CalculateCharge(float hours)
    {
        if (hours < 1.0F)
        hours = 1.0F;        // minimum charge.
        return(hours * billingRate);
    }
    
    public new string TypeName()
    {
        return("Civil Employee");
    }
}
class MainClasss{
    public static void Main(){
        Employee[]    earray = new Employee[2];
        earray[0] = new Employee("A", 15.50F);
        earray[1] = new Manager("B", 40F);
        
        Console.WriteLine("{0} charge = {1}",
        earray[0].TypeName(),
        earray[0].CalculateCharge(2F));
        Console.WriteLine("{0} charge = {1}",
        earray[1].TypeName(),
        earray[1].CalculateCharge(0.75F));
    }
}

Employee charge = 31
Civil Employee charge = 40

Using enum as a member for a struct

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
    enum orientation : byte
    {
        north = 1,
        south = 2,
        east = 3,
        west = 4
    }
    struct route
    {
        public orientation direction;
        public double distance;
    }