CallerMemberName和枚举 [英] CallerMemberName and enums

问题描述

从这个答案中：

https://stackoverflow.com/ a / 15738041/1250301

对于此问题：

如何获取属性设置的属性名称

您可以使用 CallerMemberName 来确定附加属性的属性。哪个很酷不幸的是，它似乎不适用于枚举。例如：

You can use CallerMemberName to figure out which property an attribute is attached too. Which is pretty cool. Unfortunately, it doesn't seem to work with enums. For example:

https://dotnetfiddle.net/B69FCx

public static void Main()
{   
    var mi = typeof(MyEnum).GetMember("Value1");
    var attr = mi[0].GetCustomAttribute<FooAttribute>();

    mi = typeof(Bar).GetMember("SomeProp");
    attr = mi[0].GetCustomAttribute<FooAttribute>();
}

public class Bar
{
    [Foo]
    public string SomeProp { get; set; }
}

public class FooAttribute : Attribute
{
    public FooAttribute([CallerMemberName]string propName = null)
    {
        Console.WriteLine("Propname = " + propName);
    }
}

enum MyEnum  
{
    [Foo]
    Value1,
    [Foo]
    Value2
};

propName code> MyEnum 为null，但是对于类 Bar 它可以按预期工作（即它的 SomeProp ）。有没有办法使这个或类似的工作为枚举？或者我将卡添加到 FooAttribute 中的属性，并在将属性添加到枚举时进行设置：

propName when you access it for a MyEnum is null, but for the class Bar it works as expected (i.e. it's SomeProp). Is there a way to make this or something similar work for an enum? Or am I stuck with adding a property to FooAttribute and setting it when I add the property to the enum:

public class FooAttribute : Attribute
{
    public MyEnum AttachedTo { get; set; }
}

enum MyEnum  
{
    [Foo(AttachedTo = MyEnum.Value1)]
    Value1,
    [Foo(AttachedTo = MyEnum.Value2)]
    Value2
};

哪个是乏味的，有潜在的错误倾向。

Which is tedious and has potential to be error prone.

推荐答案

CallerMemberName 不适用于程序集级别或 const 成员。因为枚举值本质上是一个const，所以你不能得到这个信息。如果您将 [Foo] 应用于中的 public const 成员，您将看到相同的行为课堂吧。

CallerMemberName is not available for Assembly level or const members. Since an Enum value is essentially a const, you can't get that information. You will see the same behavior if you apply [Foo] to a public const member on class Bar.

当我在一起测试时，内心的声音一直在尖叫着说我做错了事情。对const的属性似乎与一般的装饰者的性质相反。我觉得你进入未知的地方，这里有怪物领土。您可能想重新考虑您的设计，并考虑不同的路径。

As I was putting together a test, my inner voice kept screaming that I was doing something wrong. Having attributes on const's seems to be in opposition to the nature of decorators in general. I feel like you're getting into uncharted, 'Here there be monsters,' territory. You may want to rethink your design and consider a different path.

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