Extension method on enumeration, not instance of enumeration

Question

I have an enumeration for my Things like so:

public enum Things {    OneThing,    AnotherThing } 

I would like to write an extension method for this enumeration (similar to Prise's answer here) but while that method works on an instance of the enumeration, ala

Things thing; var list = thing.ToSelectList(); 

I would like it to work on the actual enumeration instead:

var list = Things.ToSelectList(); 

I could just do

var list = default(Things).ToSelectList(); 

But I don't like the look of that :)

I have gotten closer with the following extension method:

public static SelectList ToSelectList(this Type type) {    if (type.IsEnum)    {       var values = from Enum e in Enum.GetValues(type)                    select new { ID = e, Name = e.ToString() };       return new SelectList(values, "Id", "Name");    }    else    {       return null;    } } 

Used like so:

var list = typeof(Things).ToSelectList(); 

Can we do any better than that?

Answer 1

Extension methods only work on instances, so it can't be done, but with some well-chosen class/method names and generics, you can produce a result that looks just as good:

public class SelectList {     // Normal SelectList properties/methods go here      public static SelectList Of<T>()     {         Type t = typeof(T);         if (t.IsEnum)         {             var values = from Enum e in Enum.GetValues(type)                          select new { ID = e, Name = e.ToString() };             return new SelectList(values, "Id", "Name");         }         return null;     } } 

Then you can get your select list like this:

var list = SelectList.Of<Things>(); 

IMO this reads a lot better than Things.ToSelectList().