type casting classes mimiking enums

Question

I use a 3rd party application for output. There are several int properties and I would like to handle the different properties' int values via enum.

Property1 could be 0,1,2
Property2 could be 0,1
Property3 could be 1,2

I think I should have enum inheritance which is not option in c#.

So I solved it by using classes (I'm using Tono Nam's answer from another topic to this end: https://stackoverflow.com/a/23430174/4273304).

public class MyEnum : IEquatable<MyEnum>
{
    public static readonly MyEnum Undefined = new MyEnum(-1, "Undefined");

    public int Value { get; private set; }
    public string Name { get; private set; }

    protected MyEnum(int value, string name)
    {
        this.Value = value;
        this.Name = name;
    }

    public bool Equals(MyEnum b)
    {
        return this.Name == b.Name && this.Value == b.Value;
    }

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

    public static T Parse<T>(int value)
    {
        object obj;

        Type t_type = typeof(T);

        var fiList = t_type.GetFields(BindingFlags.Public | BindingFlags.Static).Where(f => f.FieldType == typeof(T)).ToArray();

        foreach(FieldInfo en in fiList)
        {
            object tmp = en.GetValue(null);
            if (((MyEnum)tmp).Value == value)
                return (T)tmp;
        }

        obj = MyEnum.Undefined;

        return (T)obj;
    }
}

public class MyEnumChild1 : MyEnum
{
    public static readonly MyEnumChild1 A = new MyEnumChild1(0, "A");
    public static readonly MyEnumChild1 B = new MyEnumChild1(1, "B");

    private MyEnumChild1(int value, string name)
        : base(value, name)
    {

    }
}

public class MyEnumChild2 : MyEnum
{
    public static readonly MyEnumChild2 A = new MyEnumChild2(0, "A");
    public static readonly MyEnumChild2 C = new MyEnumChild2(1, "C");

    private MyEnumChild2(int value, string name)
        : base(value, name)
    {

    }
}

public class MyEnumChild3 : MyEnum
{
    public static readonly MyEnumChild3 D = new MyEnumChild3(0, "D");
    public static readonly MyEnumChild3 E = new MyEnumChild3(1, "E");

    private MyEnumChild3(int value, string name)
        : base(value, name)
    {

    }
}

This solution serves my purposes, but I dont know how to cast an int to MyEnumChild1.
I created a parser method:

MyEnumChild1 MEC1 = MyEnum.Parse <MyEnumChild1>(1);

It seems to work fine, MEC1 is MyEnumChild1.B now, but I'm not sure of it.

How safe do you think my parser method is? Are there any mistakes in this code or can I use it safely?

Do you know any better, elegant or simpler solution for the cast?

You should post this on http://codereview.stackexchange.com/ — helb, Nov 20 '14 at 09:22

score 1 · Accepted Answer · answered Nov 20 '14 at 09:36

First, your Parse method should put a constraint on T:

public static T Parse<T>(int value) where T : MyEnum

Second, you can make it protected instead and implement a casting operator in each of the derived enums this way:

public static explicit operator MyEnumChild1(int value)
{
    return Parse<MyEnumChild1>(value);
}

And use it in a more classic way:

MyEnumChild1 mec1 = (MyEnumChild1)1

type casting classes mimiking enums

1 Answers1