Program.cs

namespace A
{
        using System;
        using System.Linq;
        using System.ComponentModel;

        public static class Program
        {
                public static void Main()
                {
                        var ceo = new CEO();
                        var worker = new Worker();

                        Console.WriteLine("{0}", ceo.GetDisplayName());
                        Console.WriteLine("{0}", worker.GetDisplayName());
                }

                private static string GetDisplayName<T>(this T self)
                {
                        var attribute = typeof(T).GetCustomAttributes(typeof(DisplayNameAttribute), false)
                                .OfType<DisplayNameAttribute>()
                                .FirstOrDefault();

                        return attribute != null ? attribute.DisplayName : "N/A";
                }
        }

        public abstract class Employee
        {
        }

        [DisplayName("Worker")]
        public class Worker : Employee
        {
        }

        public class CEO : Employee
        {
        }
}