In general your problem is connected with the fact that you want to create a generic extensions method (that's possible) but without any object reference sent as "this" parameter when calling such a method (that's not possible). So using extension methods is not an option to achieve what you want.
You could do sth like this:
public static Dictionary<string, string> EnumToDictionary(this Enum @enum)
{
var type = @enum.GetType();
return Enum.GetValues(type).Cast<string>().ToDictionary(e => e, e => Enum.GetName(type, e));
}
But this would mean that you need to operate on a certain instance of enum class to call such an extension method.
Or you could do this in such a way:
public static IDictionary<string, string> EnumToDictionary(this Type t)
{
if (t == null) throw new NullReferenceException();
if (!t.IsEnum) throw new InvalidCastException("object is not an Enumeration");
string[] names = Enum.GetNames(t);
Array values = Enum.GetValues(t);
return (from i in Enumerable.Range(0, names.Length)
select new { Key = names[i], Value = (int)values.GetValue(i) })
.ToDictionary(k => k.Key, k => k.Value.ToString());
}
And then call it like this:
var result = typeof(MyEnum).EnumToDictionary();