Get a List of my enum attributes with a generic method

Question

At start, we have this basic enum.

public enum E_Levels {

    [ValueOfEnum(\"Low level\")]
    LOW,

    [ValueOfEnum(\"Normal level\")]
    NORMAL,

    [V         


        

Answer 1

You might try casting (Enum)(object)l, changing ToValueOfEnum to take an object, or just inline the method:

public static List GetValuesOf()
{

    List levelsToReturn = new List();
    var levels = Enum.GetValues(typeof(T)).Cast();
    foreach (T value in levels)
    {
        FieldInfo fieldInfo = value.GetType().GetField(value.ToString());
        ValueOfEnum[] attribs = fieldInfo.GetCustomAttributes(typeof(ValueOfEnum), false) as ValueOfEnum[];
        levelsToReturn.Add(attribs.Length > 0 ? attribs[0].value : null);
    }

    return levelsToReturn;
}

Here's a one-line solution using the casting approach:

return new List(Enum.GetValues(typeof(T)).Cast().Select(x => x.ToValueOfEnum()));

In case you weren't clear on why T wasn't recognized as an Enum like E_Levels is, that's because you didn't specify that T : enum. Unfortunately, you can't specify that in C# (even though the CLR supports it), so other approaches like runtime checking/assuming (such as what I'm suggesting here) or post-compile code modifications (e.g. unconstrained-melody) have to be done.