An extension method which helps you to get the value of DisplayAttribute of an enum member.

GetEnumDisplayName.cs

        public static string GetEnumDisplayName(this Enum value,string unknownValue="Unknown")
        {
            if(value == null)
            {
                return unknownValue;
            }
            var type = value.GetType();
            if (!type.IsEnum) throw new ArgumentException(String.Format("Type '{0}' is not Enum", type));

            var members = type.GetMember(value.ToString());
            if (members.Length == 0) throw new ArgumentException(String.Format("Member '{0}' not found in type '{1}'", value, type.Name));

            var member = members[0];
            var attributes = member.GetCustomAttributes(typeof(DisplayAttribute), false);
            if (attributes.Length == 0) throw new ArgumentException(String.Format("'{0}.{1}' doesn't have DisplayAttribute", type.Name, value));

            var attribute = (DisplayAttribute)attributes[0];
            return attribute.GetName();
        }