C# What is the best way to create an enum that is used by multiple classes?

Question

I have an enum which is used by multiple classes. What is the best way to implement this?

Answer 1

Typically I just throw them into the namespace. It's what Microsoft did writing the .NET framework, so it's what I do too, for consistency you understand :)

Answer 2

Put it in its own file and just declare it:

public enum Foo { a, b, c, d }

Consider your namespacing of course.

Answer 3

1. Put the enums right in your namespace (or make a new namespace for them) or
2. Put them in a (static?) class somewhere if that makes more sense.

I'd keep them in their own file for easy access and good organization either way.

I usually wouldn't put them in a class unless they somehow "belong" there. Like you have a Car class with an enum for the types of car, and a Road class and Bridge class that can set limits for types of car. Car.CarType seems to be a logical organization for this...

Answer 4

XML comments help, especially if others will use it

 /// <summary>
/// Defines the types of cars we support
/// </summary>
public enum CarType
{
    /// <summary>
    /// VW - the peoples car
    /// </summary>
    Volkswagen,

Your enum name should be plural (as instructed by FxCop)

public enum CarTypes

Add numeric values and use bitwise numbering even if you don't plan to use bitwise (it's a pain to renumber later).

    Volkswagen = 1,

    /// <summary>
    /// They own lambo... can't be all that bad
    /// </summary>
    Audi = 2,

    /// <summary>
    /// Good, cheap, reliable
    /// </summary>
    Toyota = 4,

Answer 5

Here's an example of having two enums in different namespaces:

using TotallyDifferentNameSpace.Enums;

namespace EnumEx
{
    class Program
    {
        static void Main(string[] args)
        {
            CarType car = CarType.Audi;
            PetrolType pType = PetrolType.Diesel;
        }
    }

    public enum CarType
    {
        Volkswagen,
        Audi,
        Toyota,
        Ford,
        Porsche,
        Lada
    }
}

namespace TotallyDifferentNameSpace.Enums
{
    public enum PetrolType
    {
        Gasoline,
        Diesel
    }
}

Answer 6

You can put an enum is a new codefile with .cs extension, for intellisense to work make sure its part of your project/solution and ofcourse it should be a public enum so that you have a solution scope for it. If intellisense is a problem , make sure you build your solution once, i had this problem once and just a rebuild solved it. Namespacing is a good option if you want to organize your code properly and you are coding a large project. The .NET framework was large. so it has enums under namespaces just for better understanding and code organization.

Answer 7

My advice is to not use Enums at all. Use singletons instead.

Like

    public class A : ISomeInterface
    {
        public static readonly A Instance = new A();
        private A()
        {
        }

    }

    public class B : ISomeInterface
    {
        public static readonly B Instance = new A();
        private B()
        {
        }
    }

In most cases that works better and is better to extend later.

Best wishes

Matze