仿 MVC 三大特性

    public class CustomAttribute : Attribute
    {
        public int Id;
        public string Name;
        public string Reamrk;
        public string Desc;
        public CustomAttribute() : this(0, "") { }//如果没传参，使用this给默认值
        public CustomAttribute(int _id, string _name)
        {
            this.Id = _id;
            this.Name = _name;
        }
        public void Show()
        {
            Console.WriteLine($"{Id}_{Name}_{Reamrk}_{Desc}");
        }
    }

    [Custom(123,"kxy",Desc ="是个帅哥",Reamrk ="学员")]
    public class Student
    {
        [Custom(124, "wzz", Desc = "是个丑逼", Reamrk = "学员")]
        public void Study()
        {
            Console.WriteLine($"正在学习");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Student student = new Student();
            Type type = student.GetType();
            // 判断该类是否注册了CustomAttribute
            if (type.IsDefined(typeof(CustomAttribute), true))
            {
                var attribute = type.GetCustomAttribute<CustomAttribute>();
                attribute.Show();
            }

            MethodInfo method = type.GetMethod("Study");
            // 判断该方法是否注册了CustomAttribute
            if (method.IsDefined(typeof(CustomAttribute), true))
            {
                var attribute = method.GetCustomAttribute<CustomAttribute>();
                attribute.Show();
            }

            // 执行了特性之后执行方法
            student.Study();
            Console.ReadLine();
        }
    }