在dotnet核心C＃中基于海关属性值执行/拒绝功能 [英] Execute/Reject function based on customs attribute value in dotnet core C#

问题描述

我试图学习C＃dotnet核心中的属性，所以我写了下面的2类。

I'm trying to learn the attributes in C# dotnet core, so I wrote the 2 below classes.

1. 属性类：

using System;

namespace attribute
{
   // [AttributeUsage(AttributeTargets.Class)]
   [AttributeUsage(AttributeTargets.All)]
   public class MyCustomAttribute : Attribute
   {
       public string SomeProperty { get; set; }
    }


//[MyCustom(SomeProperty = "foo bar")]
public class Foo
{
    [MyCustom(SomeProperty = "user")]
    internal static void fn()
    {
        Console.WriteLine("hi");
    }
  }
}

主类：

using System;
using System.Reflection;

namespace attribute
{
    public class Program
    {
        public static int Main(string[] args)
        {

            var customAttributes = (MyCustomAttribute[])typeof(Foo).GetTypeInfo().GetCustomAttributes(typeof(MyCustomAttribute), true);
        if (customAttributes.Length > 0)
        {
            var myAttribute = customAttributes[0];
            string value = myAttribute.SomeProperty;
            // TODO: Do something with the value
            Console.WriteLine(value);
            if (value == "bar")
                Foo.fn();
            else
                Console.WriteLine("Unauthorized");
        }
        return 0;
    }
  }
}

我需要函数 Foo.fn（）来执行，如果 SomeProperty 元素在 MyCustomAttribute 等于 bar 。
如果我将其应用于类级别，但在功能级别中不起作用，我的代码可以正常工作

I need the function Foo.fn() to be executed if the SomeProperty element in the MyCustomAttribute is equal to bar. My code work fine if I applied it into the class level, but not working on the function level

重要提示
我对此很陌生，因此欢迎任何改进我的代码的建议或反馈。谢谢

IMPORTANT NOTE I'm very new to this, so any advice or feedback to improve my code, is welcomed. thanks

推荐答案

您的解决方案是找到声明的方法&在该方法中找到该属性。

your solution is to find the declared method & in that method find the attribute.

var customAttributes =  (MyCustomAttribute[])((typeof(Foo).GetTypeInfo())
.DeclaredMethods.Where(x => x.Name == "fn")
.FirstOrDefault())
.GetCustomAttributes(typeof(MyCustomAttribute), true);

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