StringEnum 0.0.2

StringEnum

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

Usage:

///<completionlist cref="HexColor"/> 
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

• Your StringEnum interface looks somewhat similar to a regular enum:

    // Static Parse Method
    HexColor.Parse("#FF0000") // => HexColor.Red
    HexColor.Parse("#ff0000", caseSensitive: false) // => HexColor.Red
    HexColor.Parse("invalid") // => throws InvalidOperationException

    // Static TryParse method.
    HexColor.TryParse("#FF0000") // => HexColor.Red
    HexColor.TryParse("#ff0000", caseSensitive: false) // => HexColor.Red
    HexColor.TryParse("invalid") // => null

    // Parse and TryParse returns the preexistent instances
    object.ReferenceEquals(HexColor.Parse("#FF0000"), HexColor.Red) // => true

    // Conversion from your `StringEnum` to `string`
    string myString1 = HexColor.Red.ToString(); // => "#FF0000"
    string myString2 = HexColor.Red; // => "#FF0000" (implicit cast)

• Intellisense will suggest the enum name if the class is annotated with the xml comment <completitionlist>. (Works in both C# and VB): i.e.

Instalation

Either:

• Install StringEnum NuGet package, which is 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, or follow the steps explained here

Extensibility tips

• 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");
      public static readonly Color Green = New("Greem");
  
      // Add the following line
      public static implicit operator Color(string stringValue) 
          => Parse(stringValue, caseSensitive: false); 
  }
  
  // usage:
  Color x = "Blue"; // same as Color.Parse("Blue", caseSensitive: false)
  // or given a method:
  void PaintWall(Color wallColor)
  // you can call
  PaintWall("Blue");
  

• To allow any string to be a casted as your StringEnum value, you may expose the New() method as public:

  public new static MyEnum 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);
  

  However, do not use the New() method, with user-entered strings, as they will be stored in memory in the internal ValueList cache used for Parse and TryParse.