Enum to list as an extension?

Question

I have various enums that I use as sources for dropdown lists, In order to provide for a user-friendly description, I added a Description attribute to each enum, an

Answer 1

Whenever I need an enumeration (a static list of known values) that need to have something more than just a mere integer value and a string counterpart, I end up using this Enumeration Utility class that essentially gives me java-like enumeration behavior.

So that would be my first option if I were on op's shoes as it would make it really trivial to achieve what he/she wants.

But, assuming this is not an option for op and she/he need to stick with C# enums, I would use a combination of both ehsan-sajjad and frank-j solutions:

1. Have an extension method to return the description of a given enum item, which is pretty much what op had already;
2. Have a static helper method to return a dictionary of items and their respective descriptions for a given enum type.

Here is how I would implement this:

public static class EnumUtils
{
    public static string GetDescription(this Enum enumVal)
    {
        var type = enumVal.GetType();
        var memInfo = type.GetMember(enumVal.ToString());
        var attributes = memInfo[0].GetCustomAttributes(typeof (DescriptionAttribute), false);

        return (attributes.Length > 0) ? ((DescriptionAttribute) attributes[0]).Description : null;
    }

    public static Dictionary GetItemsWithDescrition()
    {
        var enumType = typeof(TEnum);
        if (!enumType.IsEnum)
        {
            throw new InvalidOperationException("TEnum must be an enum type");
        }

        return Enum
                .GetValues(enumType)
                .Cast()
                .ToDictionary(enumValue => enumValue, enumValue => GetDescription(enumValue as Enum));
    }
}

And here is what the usage would look like:

public class EnumUtilsTests
{
    public enum MyEnum
    {
        [Description("Um")]
        One,
        [Description("Dois")]
        Two,
        [Description("Tres")]
        Three,
        NoDescription
    }

    public void Should_get_enum_description()
    {
        MyEnum.One.GetDescription().ShouldBe("Um");
        MyEnum.Two.GetDescription().ShouldBe("Dois");
        MyEnum.Three.GetDescription().ShouldBe("Tres");
        MyEnum.NoDescription.GetDescription().ShouldBe(null);
    }

    public void Should_get_all_enum_values_with_description()
    {
        var response = EnumUtils.GetItemsWithDescrition();

        response.ShouldContain(x => x.Key == MyEnum.One && x.Value == "Um");
        response.ShouldContain(x => x.Key == MyEnum.Two && x.Value == "Dois");
        response.ShouldContain(x => x.Key == MyEnum.Three && x.Value == "Tres");
        response.ShouldContain(x => x.Key == MyEnum.NoDescription && x.Value == null);
    }
}