获取属性特性几种方法

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Reflection;

namespace ConsoleApp3
{
    
    internal class Program
    {
    
        public EventHandler<EventArgs> OnClick;

        static void Main(string[] args)
        {
    
            Person person = new Person();
            person.Name = "aoteman";
            string s = GetDecription();
            //AA();
            //BB();
            //CC();
            //Console.WriteLine(ss);
            Console.ReadLine();
        }


        public static string GetDecription()
        {
    
            Person person = new Person();
            var field = person.GetType().GetProperty("Name");
            var customAttribute = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute));
            return customAttribute == null ? person.ToString() : ((DescriptionAttribute)customAttribute).Description;


            //string str = "";
            //Desc desc = new Desc();
            //PropertyDescriptor pd = TypeDescriptor.GetProperties(typeof(Desc))["des"];
            //DescriptionAttribute description = pd == null ? null : pd.Attributes[typeof(DescriptionAttribute)] as DescriptionAttribute;
            //str = description == null ? "" : description.Description;


            
            string s = person.GetType().GetProperty("Name").GetGetMethod().Invoke(person, null).ToString();
        }

        public static void AA()
        {
    
            string str = "";
            PropertyInfo pi = typeof(Desc).GetProperty("des");
            foreach (object obj in pi.GetCustomAttributes(false))
            {
    
                if (obj is DescriptionAttribute)
                {
    
                    str = (obj as DescriptionAttribute).Description;
                }
            }
        }

        public static void BB()
        {
    
            string str = "";
            Desc desc = new Desc();
            AttributeCollection attributes = TypeDescriptor.GetAttributes(desc);
            DescriptionAttribute da = (DescriptionAttribute)attributes[typeof(DescriptionAttribute)];
            if (attributes.Contains(da))
            {
    
                str = da.Description;
            }
        }

        public static void CC()
        {
    
            string str = "";
            Type myType = typeof(Desc);
            foreach (object obj in myType.GetCustomAttributes(false))
            {
    
                if (obj is DescriptionAttribute)
                {
    
                    str = (obj as DescriptionAttribute).Description;
                }
            }
        }


        public static void ShowPerson(Person person)
        {
    
            int i = person?.Age ?? 0;
        }

    }

    class Person
    {
    
        [Description("this is name"), Category("Layout")]
        public string Name {
     get; set; }
        [Description("this is age"), Category("Layout")]
        public int Age {
     get; set; }
    }
    public struct Desc
    {
    
        private byte val1;
        [Description("一个属性")]
        public byte des
        {
    
            get {
     return val1; }
            set {
     val1 = value; }
        }
    }
}