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CSharp examples for Custom Type:Enum

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Introduction

You can combine enum members.

To prevent ambiguities, members of a combinable enum require explicitly assigned values, typically in powers of two.

For example: 

[Flags]
public enum Directions { None=0, Left=1, Right=2, Top=4, Bottom=8 }

To work with combined enum values, you use bitwise operators, such as | and &.

These operate on the underlying integral values: 

                                                                                                   
[Flags]
public enum Directions { None=0, Left=1, Right=2, Top=4, Bottom=8 }                          

                                                                                                  
Directions leftRight = Directions.Left | Directions.Right;

if ((leftRight & Directions.Left) != 0)
  Console.WriteLine ("Includes Left");     // Includes Left

string formatted = leftRight.ToString();   // "Left, Right"

Directions s = Directions.Left;
s |= Directions.Right;
Console.WriteLine (s == leftRight);   // True

s ^= Directions.Right;               // Toggles Directions.Right
Console.WriteLine (s);                // Left

By convention, a combinable enum type is given a plural rather than singular name.

You can include combination members within an enum declaration itself: 

[Flags]
public enum Directions
{
   None=0,
   Left=1, Right=2, Top=4, Bottom=8,
   LeftRight = Left | Right,
   TopBottom = Top  | Bottom,
   All       = LeftRight | TopBottom
}

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