C# 反射（reflection）获取元数据

using System;
using System.Linq;
using System.Reflection;

namespace ReflectionPractice
{
    [AttributeUsage(AttributeTargets.All, AllowMultiple = true, Inherited = true)]
    
    public class HelpAttribute : Attribute
    {
        public HelpAttribute(){}
        
        public HelpAttribute(String Description_in, Int64 idPage_in, String author_in)
        {
            this.description = Description_in;
            this.idPage = idPage_in;
            this.author = author_in;
        }
        
        protected String description;    
        protected Int64 idPage;    
        protected String author;        
        
        public String Description
        {
            get { return this.description; }
        }
        
        public Int64 IdPage
        {
            get { return this.idPage; }
        }
        
        public String Author
        {
            get { return this.author; }
        }
    }

    [Help("this is a HelpAttribute use class", 15, "zhangsan")]
    [Help("this is a HelpAttribute2 use class", 32, "lisi")]
    public class UseHelpAttribute
    {
        public UseHelpAttribute(){}
        
        public UseHelpAttribute(String nameClass_in)
        {
            this.nameClassBase = nameClass_in;
        }
        
        protected String nameClassBase;
        
        public String NameClassBase
        {
            get { return this.nameClassBase; }
        }
        
        [Help("this is a base Display function", 99, "base you guess")]
        public void BaseDisplay()
        {
            Console.WriteLine(nameClassBase);
        }
    }
    
    
    public class UseHelpAttributeDerive : UseHelpAttribute
    {
        public UseHelpAttributeDerive(){}
        
        public UseHelpAttributeDerive(String nameClass_in)
        {
            this.nameClass = nameClass_in;
        }
        
        protected String nameClass;
        
        public String NameClass
        {
            get { return this.nameClass; }
        }
        
        [Help("this is a Display function", 100, "you guess")]
        public void Display()
        {
            Console.WriteLine(nameClass);
        }
    }
    
    
    class Program
    {
        public static void Main(string[] args)
        {
            // TODO: Implement Functionality Here                      
            UseHelpAttributeDerive     UseHelpAttributeDeriveObject =  new UseHelpAttributeDerive("DeriveClass");
            UseHelpAttributeDeriveObject.Display();        
            
            //用反射获取元数据
            Type info = typeof(UseHelpAttributeDerive);
        
            //遍历类特性            
            foreach (Object attributes in info.GetCustomAttributes(true))
            {
                HelpAttribute HelpAttrObject = attributes as HelpAttribute;
                        
                Console.WriteLine("描述：{0}", HelpAttrObject.Description);
                Console.WriteLine("页：{0}", HelpAttrObject.IdPage);
                Console.WriteLine("作者：{0}", HelpAttrObject.Author);
                Console.WriteLine("");
            }
            
            //遍历类方法
            foreach (MethodInfo m in info.GetMethods())
            {
                foreach(Attribute attributes in m.GetCustomAttributes(false))
                {    
                    HelpAttribute HelpAttrObject = attributes as HelpAttribute;
                    
                    if(HelpAttrObject != null)
                    {                
                        Console.WriteLine("描述：{0}", HelpAttrObject.Description);
                        Console.WriteLine("页：{0}", HelpAttrObject.IdPage);
                        Console.WriteLine("作者：{0}", HelpAttrObject.Author);
                        Console.WriteLine("");
                    }
                }
            }
            
            Console.ReadKey(true);
        }
    }
}

运行结果;