C# Language Pocket Reference

Enums

Enums specify a group of named numeric constants:

public enum Direction {North, East, West, South}

Unlike in C, enum members must be used with the enum type name. This resolves naming conflicts and makes code clearer:

Direction walls = Direction.East;

By default, enums are assigned integer constants 0, 1, 2, etc. You may optionally specify an alternative numeric type to base your enum and explicitly specify values for each enum member:

[Flags]
public enum Direction : byte {
   North=1, East=2, West=4, South=8
}
Direction walls = Direction.North | Direction.West;
if((walls & Direction.North) != 0)
    System.Console.WriteLine("Can't go north!");

The [Flags] attribute is optional and informs the runtime that the values in the enum can be bit-combined and should be decoded accordingly in the debugger or when outputting text to the console. For example:

Console.WriteLine(walls); // Displays "North, West"
Console.WriteLine((int) walls); // Displays "5"

The System.Enum type also provides many useful static methods for enums that let you determine the underlying type of an enum, check if a specific value is supported, initialize an enum from a string constant, retrieve a list of the valid values, and other common operations such as conversions. Here is an example of the usage:

using System; public enum Toggle : byte { Off=0, On=1 } class Test { static void Main( ) { Type t = Enum.GetUnderlyingType(typeof(Toggle)); Console.WriteLine(t); // Prints "Byte" bool bDimmed = Enum.IsDefined(typeof(Toggle), ...