Enumeration types (C# reference)

enum Season
{
    Spring,
    Summer,
    Autumn,
    Winter
}

enum ErrorCode : ushort
{
    None = 0,
    Unknown = 1,
    ConnectionLost = 100,
    OutlierReading = 200
}

 

enum 과 switch 문 활용 예)

public enum WhiteIpRequestState
{
    NoRequest = 0,
    Requested = 1,
    Approved = 2,
    Rejected = 3
}

WhiteIpRequestState whiteIpRequestState = ...
           
switch(whiteIpRequestState)
{
    case WhiteIpRequestState.NoRequest:
    case WhiteIpRequestState.Rejected:
        return RedirectToAction("WhiteIpRequest", "Login");
    case WhiteIpRequestState.Requested:
        return RedirectToAction("WhiteIpRequestInProcess", "Login");
    default:
        break;
}

 

[Flags]
public enum Days
{
    None      = 0b_0000_0000,  // 0
    Monday    = 0b_0000_0001,  // 1
    Tuesday   = 0b_0000_0010,  // 2
    Wednesday = 0b_0000_0100,  // 4
    Thursday  = 0b_0000_1000,  // 8
    Friday    = 0b_0001_0000,  // 16
    Saturday  = 0b_0010_0000,  // 32
    Sunday    = 0b_0100_0000,  // 64
    Weekend   = Saturday | Sunday
}

public class FlagsEnumExample
{
    public static void Main()
    {
        Days meetingDays = Days.Monday | Days.Wednesday | Days.Friday;
        Console.WriteLine(meetingDays);
        // Output:
        // Monday, Wednesday, Friday

        Days workingFromHomeDays = Days.Thursday | Days.Friday;
        Console.WriteLine($"Join a meeting by phone on {meetingDays & workingFromHomeDays}");
        // Output:
        // Join a meeting by phone on Friday

        bool isMeetingOnTuesday = (meetingDays & Days.Tuesday) == Days.Tuesday;
        Console.WriteLine($"Is there a meeting on Tuesday: {isMeetingOnTuesday}");
        // Output:
        // Is there a meeting on Tuesday: False

        var a = (Days)37;
        Console.WriteLine(a);
        // Output:
        // Monday, Wednesday, Saturday
    }
}

 

public enum Season
{
    Spring,
    Summer,
    Autumn,
    Winter
}

public class EnumConversionExample
{
    public static void Main()
    {
        Season a = Season.Autumn;
        Console.WriteLine($"Integral value of {a} is {(int)a}");  // output: Integral value of Autumn is 2

        var b = (Season)1;
        Console.WriteLine(b);  // output: Summer

        var c = (Season)4;
        Console.WriteLine(c);  // output: 4
    }
}

 

An enumeration type (or enum type) is a value type defined by a set of named constants of the underlying integral numeric type. To define an enumeration type, use the enum keyword and specify the names of enum members: