StringEnum 0.0.1

StringEnum

StringEnum is a base class for creating string-valued enums in .NET. It is just one file that you can copy & paste into your projects, or install via NuGet package named StringEnum.

Usage:

class HexColor : StringEnum<HexColor>
{
    public static readonly HexColor Blue = New("#FF0000");
    public static readonly HexColor Green = New("#00FF00");
    public static readonly HexColor Red = New("#000FF");
}

Features

• Implicit conversion from StringEnum to string

string myString1 = HexColor.Red; // implicit cast to string => "#FF0000"
string myString2 = HexColor.Red.ToString(); // also returns => "#FF0000"

string myCss = $"{background-color: " + HexColor.Red + ";}";

• Conversion from string to the StringEnum class with Parse and TryParse static methods. It does not uses reflection. O(N) time. Always returns preexistent instances. They will only match with defined

HexColor MyParam = HexColor.TryParse("#FF0000"); // returns HexColor.Red
HexColor MyParam = HexColor.TryParse("#ff0000", caseSensitive: false); // => HexColor.Red ;
HexColor MyParam = HexColor.TryParse("invalid"); // => null;
HexColor MyParam = HexColor.Parse("invalid"); // throws InvalidOperationException;
object.ReferenceEquals(HexColor.Parse("#FF0000"), HexColor.Red) // => true

• Comparison by underlying string value:

Console.WriteLine(HexColor.Red == "#FF0000") // => true (case sensitive)
Console.WriteLine(HexColor.Red == HexColor.Parse("#ff0000", caseSensitive: false)) // => true (case insensitive)

Instalation

Either:

• Install StringEnumg NuGet package, it's based on .Net Standard 1.0 so it runs on .Net Core >= 1.0, .Net Framework >= 4.5, Mono >= 4.6, etc.
• Or copy StringEnum.cs base class to your project.
• For Newtonsoft.Json serialization support, copy this extended version instead. StringEnum.cs.

Extensibility tips

• Newtonsoft.Json serialization support explained here

• You may add implicit casting from string to your StringEnum, by binding the implicit cast operator to the Parse method in the target class.

class Color : StringEnum<Color>
{
    public static readonly Color Blue = New("Blue");
    ..other members...

    public static implicit operator Color(string stringValue) => Parse(stringValue, caseSensitive: false);
}

// usage:
Color x = "Blue"; // same as Color.Parse("Blue", caseSensitive: false)
// or given:
void PaintWall(Color wallColor)
// you can call 
PaintWall("Blue");

• To allow any string to be a casted as the enum, expose the New() method:

public new static TestEnum New(string value) => StringEnum<MyEnum>.New(value);

Or implement a special implicit cast:

public static implicit operator MyEnum(string stringValue) => TryParse(stringValue, true) ?? New(stringValue);

But do not use this with user-entered strings, as they are stored ad-eternum in the internal ValueList used for Parse and TryParse.