まさるblog

using System;

namespace ConsoleApplication1
{
  class TypedEnum<T>
  {
    public T Value { get; private set; }

    public TypedEnum(T value)
    {
      this.Value = value;
    }

    public override string ToString()
    {
      return this.Value.ToString();
    }

    public override int GetHashCode()
    {
      return 0;
    }

    public override bool Equals(object obj)
    {
      if (obj is TypedEnum<T>)
      {
        return this.Value.Equals(((TypedEnum<T>)obj).Value);
      }
      else
      {
        return false;
      }
   }

    public static bool operator ==(TypedEnum<T> a, TypedEnum<T> b)
    {
      if (Object.Equals(a, null))
      {
        return Object.Equals(b, null);
      }
      return a.Equals(b);
    }

    public static bool operator !=(TypedEnum<T> a, TypedEnum<T> b)
    {
      if (Object.Equals(a, null))
      {
        return !Object.Equals(b, null);
      }
      return !a.Equals(b);
    }
  }

  // ISO 5218を元に作成
  class 性別 : TypedEnum<string>
  {
    private 性別(string value) : base(value) { }
    public static readonly 性別 男 = new 性別("1");
    public static readonly 性別 女 = new 性別("2");
  }

  class Program
  {
    static void Main(string[] args)
    {
      性別 sex;

      sex = 性別.男;
      Console.WriteLine("男 : {0}", sex);

      sex = 性別.女;
      Console.WriteLine("女 : {0}", sex);

      String value = sex.Value;
      Console.WriteLine("女 : {0}", value);

      Console.WriteLine("true : {0}", sex == 性別.女);
      Console.WriteLine("false : {0}", sex == 性別.男);

      Console.WriteLine("true : {0}", 性別.男 == 性別.男);
      Console.WriteLine("true : {0}", 性別.女 == 性別.女);

      Console.WriteLine("false : {0}", 性別.男 == 性別.女);
      Console.WriteLine("false : {0}", 性別.女 == 性別.男);

      Console.WriteLine("false : {0}", 性別.男 == null);
      Console.WriteLine("false : {0}", sex == null);

      Console.WriteLine("false : {0}", null == 性別.男);
      Console.WriteLine("false : {0}", null == sex);

      sex = null;
      Console.WriteLine("true : {0}", sex == null);
      Console.WriteLine("true : {0}", null == sex);
    }
  }
}