public class MyAttribute : Attribute
    {
        /// <summary>
        /// 代码
        /// </summary>
        public string Code { get; set; }

        /// <summary>
        /// 描述
        /// </summary>
        public string Msg { get; set; }

        public MyAttribute() { }

        public MyAttribute(string code,string msg)
        {
            this.Code = code;
            this.Msg = msg;
        }
    }

    [MyAttribute("C01","类属性描述")]
    public class AttributeTest
    {
        [My("C02","属性描述")] // 等价于      [MyAttribute("C02","属性描述")]
        public string Field { get; set; }

        [My("C03", "方法描述")]
        public void Method()
        {

        }
    }

        static void Main(string[] args)
        {
            // 获取类的属性描述
            var classIfno = typeof(AttributeTest).GetCustomAttribute<MyAttribute>();

            // 获取指定属性的属性描述
            var fieldIfno = typeof(AttributeTest).GetProperty("Field").GetCustomAttribute<MyAttribute>();

            // 获取指定方法的属性描述
            var methodIfno = typeof(AttributeTest).GetMethod("Method").GetCustomAttribute<MyAttribute>();

            Console.WriteLine(classIfno.Msg + "  " + fieldIfno.Msg + "  " + methodIfno.Msg);

            Console.ReadLine();
        }