[AttributeUsageAttribute(AttributeTargets.All, AllowMultiple = true, Inherited = true)]

    class MyNewAttribute : System.Attribute

    {

        //

    }

    class Program

    {

        static void Main(string[] args)

        {

            Animal animals = Animal.Dog | Animal.Cat;

            Console.WriteLine(animals.ToString());

        }

    }

    [Flags]

    enum Animal

    {

        Dog = 0x0001,

        Cat = 0x0002,

        Duck = 0x0004,

        Chicken = 0x0008

    }

        [System.Runtime.InteropServices.DllImport("User32.dll")]

        public static extern int MessageBox(int hParent, string msg, string caption, int type);

        static void Main(string[] args)

        {

            MessageBox(, "How to use attribute in .NET", "Anytao_net", );

        }