Is enum value defined

using System;

public enum WeekDay{

   Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday

}

class Test
{
    static void Main()
    {
        WeekDay day = (WeekDay)111;

        if (Enum.IsDefined(day.GetType(),day))
        {
            Console.WriteLine("defined");
        }
        else
        {
            Console.WriteLine("not defined");

        }

    }
}