Typesafe enum or attribute enum?

Question

My first approach looked like it would work very nicely until I got a runtime error I had no idea how to solve at var name = ((LCData)attributes[0]).Name; about index out of range. Practically I was just copying the code I found at Getting attributes of Enum's value so I was not 100% sure what it actually did. So when the following code didn't work, I moved on to another solution.

public enum Identification : ushort

{

    [LCAttribute("IMG_BG01_Greens")]
    BG01_Greens = 0,

    [LCAttribute("Rabbit", "IMG_E01_Rabbit")]
    ENEMY_E01_Rabbit = 2000,
}

public static class Enums
{
    public static LCData GetInfo(Identification id)
    {
        var type = typeof(Identification);
        var memInfo = type.GetMember(id.ToString());
        var attributes = memInfo[0].GetCustomAttributes(typeof(LCData), false);
        var name = ((LCData)attributes[0]).Name;
        var tex = ((LCData)attributes[0]).Texture;

        LCData data;
        data.Name = name;
        data.Texture = tex;
        return data;
    }
}

public struct LCData
{
    public string Name;
    public string Texture;

    public LCData(Identification id)
    {
        this = Enums.GetInfo(id);
    }
}

public class LCAttribute : System.Attribute
{
    private string _Name;
    public string Name
    {
        get
        {
            return _Name;
        }
    }

    private string _Texture;
    public string Texture
    {
        get
        {
            return _Texture;
        }
    }

    public LCAttribute(string texture)
    {
        _Texture = texture;
    }

    public LCAttribute(string name, string texture)
    {
        _Name = name;
        _Texture = texture;
    }
}

Secondly I tried the typesafe enum approach. This had 2 fatal weaknesses I couldn't find a solution for:

1) I cannot get a list of available enum entries for looping operations.

2) I cannot get the corresponding enum entry by an id number.

public sealed class Identification
{

    private readonly ushort _ID;
    private readonly string _Name;
    private readonly string _Tex;

    public static readonly Identification BG01_Greens = new Identification(0, "IMG_BG01_Greens");
    public static readonly Identification ENEMY_E01_Rabbit = new Identification(2000, "Rabbit", "IMG_E01_Rabbit");

    private Identification(ushort id, string tex)
    {
        _ID = id;
        _Tex = tex;
    }

    private Identification(ushort id, string name, string tex)
    {
        _ID = id;
        _Name = name;
        _Tex = tex;
    }
    public ushort ID { get { return _ID; } }
    public string Name { get { return _Name; } }
    public string Texture { get { return _Tex; } }
}

How should I proceed? Why doesn't my first solution work?

Why don't you just use a `Dictionary`? It's type-safe, lightning fast, and you can enumerate over it. — Robert Harvey, Dec 17 '13 at 17:44
Similar: [Simplification of Enum and its associated values](http://stackoverflow.com/questions/14392428/simplification-of-enum-and-its-associated-values). Although that is not based on attributes. — Theraot, Dec 17 '13 at 17:57

score 0 · Answer 1 · edited May 23 '17 at 11:50

You are confusing LCData and LCAttriubte. Because LCAttribute is a valid attribute, but you are trying to use LCData as the attribute. (By the way, probably you don't need two separate types... but I bear with you).

This the ammended code:

public enum Identification : ushort
{
    [LCAttribute("IMG_BG01_Greens")] //Look the type of the attributes is LCAttribute
    BG01_Greens = 0,

    [LCAttribute("Rabbit", "IMG_E01_Rabbit")]
    ENEMY_E01_Rabbit = 2000,
}

public static class Enums
{
    public static LCData GetInfo(Identification id)
    {
        var type = typeof(Identification);
        var memInfo = type.GetMember(id.ToString());
        //this will return an array of LCAttributes
        var attributes = memInfo[0].GetCustomAttributes(typeof(LCAttribute), false);
        //I tell you they are LCAttribute not LCData
        var name = ((LCAttribute)attributes[0]).Name;
        var tex = ((LCAttribute)attributes[0]).Texture;
        //If the above were an LCData why would create a new one here? [Rethorical]
        LCData data;
        data.Name = name;
        data.Texture = tex;
        return data;
    }
}

Note: For altenatives approaches and maybe some insight into this approach you can see my answer to How do you make an 'enum' that has data tied to it?. The approach you use here is listed under "Custom Attributes".

I tried casting it as LCAttribute before but it gave the index out of range error so in a desperate try I also tried casting it as LCData (which followed the copied code version), but now it looks like my problem can be solved by a simple Dictionary, thanks for help! — user3110376, Dec 17 '13 at 18:14
@user3110376 If you were getting index out of range, it may mean you were unable to read the attribute, as if it weren't there. The alternative in the linked answer have some extra checks for that case. — Theraot, Dec 17 '13 at 18:17

Typesafe enum or attribute enum?

1 Answers1