使用 System.Attribute 类 [英] Using System.Attribute class

问题描述

我陷入了这样一种情况:使用 System.Attribute 类似乎(乍一看)是个好主意.

我有一个要在我的应用程序中打印的对象，我需要在每个属性之前添加一个标签(或者它之前只是一个字符串).我可以将每个属性硬编码为:

Console.WriteLine("颜色:"+obj.color);Console.WriteLine("尺寸:"+obj.size);

对每个属性依此类推.但不是它，我试图创建一个不需要硬编码这个标签"的代码，这样我就可以动态打印每个属性.

我得到了类似的东西，使用 System.Attribute 类:

公共类 MyObject{[MyCustomLabel("颜色:")]公共字符串颜色；[MyCustomLabel("尺寸:")]公共字符串大小；//等等...}

所以我的问题来了:检索这个属性的值不是不可能的，但它不友好，因为我不得不为它使用一些反射.

我并不是真的害怕使用反射，但似乎我正在为不是为它创建的东西使用属性.

我想知道使用属性的最佳位置在哪里，如果这真的是使用它的情况.

解决方案

属性和反射齐头并进.除了一些编译器/运行时属性之外，没有办法在不反映代码的情况下使用它们.

也就是说，您的方法是合理的，您可能想看看 System.ComponentModel 命名空间中的属性，这些属性有许多类来用有用的元数据装饰属性.

I got myself in a situation where using the System.Attribute class seemed (at first glance) to be a good idea.

I have an object to be printed in my application, and I need a label before each property (or just a string before it). I could put each property hardcoded like:

Console.WriteLine("Color:"+obj.color);
Console.WriteLine("Size:"+obj.size);

And so on for each property. But instead of it, I was trying to create a code where this 'label' doesn't needed to be hardcoded, so I could print every property dynamically.

I got something like that, using System.Attribute class:

public class MyObject 
{
    [MyCustomLabel("Color:")]
    public string Color;

    [MyCustomLabel("Size:")]
    public string Size;
    //etc...
}

So here comes my problem: retrieving this Attribute's value is not impossible, but it's not friendly since I had to use some reflection for it.

I'm not really scared of using reflection, but it seemed that I was using attributes for something that it wasn't created for.

I wonder where are the best places for using attributes, and if this is really a situation for using it.

解决方案

Attributes and reflection go hand in hand. With the exception of some compiler/runtime attributes, there's no way to use them with out reflecting over the code.

That said, your approach is reasonable, and you might want to take a look at the attributes in the System.ComponentModel namespace which have a number of classes to decorate properties with useful metadata.

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