创建一个特性ShowAttribute继承Attribute

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MyAttribute.ShowExtend
{
    //表示现在可以标记多个特性和子类特性
    [AttributeUsage(AttributeTargets.All,AllowMultiple =true,Inherited =true)]
    public class ShowAttribute:Attribute
    {
        public string ShowInfo { get; set; }
        public void Show()
        {
            Console.WriteLine(ShowInfo);
        }
    }
}

首先创建一个ShowTest测试类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MyAttribute.ShowExtend
{
    [Show(ShowInfo="我是在类上的特性")]
    [Show(ShowInfo = "我是在类上的第二个特性")]
    public class ShowTest
    {
        [Show(ShowInfo = "我是在方法上的特性")]
        public void TestMethod()
        {

        }
        [Show(ShowInfo = "我是在属性上的特性")]
        public string TestProper { get; set; }
        [Show(ShowInfo = "我是在字段上的特性")]
        public string TestField;
    }
}

创建一个特性调用类，而且具有泛型的扩展方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace MyAttribute.ShowExtend
{
    //扩展方法实现泛型
    public static class InvokeCenter
    {
        public static void InvokeManager<T>( this T showTest) where T:new()
        {
            Type type = showTest.GetType();
            if (type.IsDefined(typeof(ShowAttribute),true))
            {
                //在类上查找特性
                object[] attributes = type.GetCustomAttributes(typeof(ShowAttribute), true);
                foreach (ShowAttribute attribute in attributes)
                {
                    attribute.Show();
                }
                //在方法上查找特性
                foreach (MethodInfo method in type.GetMethods())
                {
                    if (method.IsDefined(typeof(ShowAttribute), true))
                    {
                        object[] attributeMethods = type.GetCustomAttributes(typeof(ShowAttribute), true);
                        foreach (ShowAttribute attribute in attributeMethods)
                        {
                            attribute.Show();
                        }
                    }
                }
                //在属性上查找特性
                foreach (PropertyInfo property in type.GetProperties())
                {
                    if (property.IsDefined(typeof(ShowAttribute), true))
                    {
                        object[] attributeMethods = property.GetCustomAttributes(typeof(ShowAttribute), true);
                        foreach (ShowAttribute attribute in attributeMethods)
                        {
                            attribute.Show();
                        }
                    }
                }
                //在字段上查找特性
                foreach(FieldInfo fieldInfo in type.GetFields())
                {
                    if (fieldInfo.IsDefined(typeof(ShowAttribute), true))
                    {
                        object[] attributeFields = fieldInfo.GetCustomAttributes(typeof(ShowAttribute), true);
                        foreach (ShowAttribute attribute in attributeFields)
                        {
                            attribute.Show();
                        }
                    }
                }

            }
        }
    }
}

在Main函数中进行调用

static void Main(string[] args)
{
    //实验二，普通方法，要实例化对象作为参数进行传递。特性调用中心也不需要static类static方法
    //ShowTest showTest = new ShowTest();
    //InvokeCenter invokeCenter = new InvokeCenter();
    //invokeCenter.InvokeManager<ShowTest>(showTest);

    ShowTest showTest = new ShowTest();
    showTest.InvokeManager();
    Console.ReadKey(); 
}