How to get an enum value with either one of two attribute values

Question

Edit: I updated the post to use a Guid instead of int . Thanks to those below who have pointed out that using int doesn't do anything since the base type of the enum is int .

I have an enum, let's say it's

public enum AnimalType
{
    [Animal("00000000000000000000000000000001")]
    Bear = 0,

    [Animal("00000000000000000000000000000002")]
    Cat = 1,

    [Animal("00000000000000000000000000000003")]
    Dog = 2
}

This enum uses the Animal attribute, defined as:

public class AnimalAttribute : Attribute
{
    public AnimalAttribute(Guid id)
    {
        this.AnimalId = id;
    }

    public AnimalAttribute(string id)
    {
        this.AnimalId = new Guid(id);
    }

    public Guid AnimalId { get; private set; }

    // Some more properties

}

As you can see there are two constructors for AnimalAttribute , allowing to accept the id as a string or Guid . The AnimalType enum uses the string constructor.

So as of now the enum value can only be accessed by knowing the id. Let's say that if I don't know the id corresponding to a particular enum value, I can also access the enum values using some name/description corresponding to each enum value (probably just "Bear" for Bear, etc.). My question is, how do I set this up so the AnimalAttribute can accept either the id (and either as a string or a Guid) or the name/description corresponding to the enum value? I would like to make another constructor for AnimalAttribute like so:

public AnimalAttribute(string name)
{
    this.AnimalName = name; // assume there is an AnimalName property.
}

Then I could add another attribute to each enum value like so:

[Animal("00000000000000000000000000000001")]
[Animal("Bear")]
Bear = 0,

And so I could supply either value and I'll be able to get the enum value. The problem with this is that I can't make the constructor in AnimalAttribute accepting string name since there is already another constructor accepting string id . If I can't do that then I thought I could make the constructor with optional parameters. Is there an easy way to set this up?

Answer 1

Not sure what you're goal is, but you may be over complicating this. It doesn't make sense to use an enumeration with its int value then define an attribute with a different int value.

Look at using a DescriptionAttribute instead. It's built-in and will do what you need.

Check out Getting attributes of Enum's value

Answer 2

Forgive me if I'm misunderstanding some details of your scenario, but if the AnimalId property of the Animal attribute is always going to equal the int value of the Enum element then isn't the Animal attribute unnecessary? Couldn't you just do the following:

Enum:

public enum AnimalType
{
    Bear = 0,
    Cat = 1,
    Dog = 2
}

To get the int value just cast the enum:

int animalVal = (int)AnimalType.Bear;

To get the animal name by value:

string animalName = Enum.GetName(typeof(AnimalType), 0);