将属性与 .net 中的代码生成属性相关联

问题描述

我希望在 .NET 中为公共属性设置属性，但是我无权访问显式属性本身，因为这是在另一个文件中生成的代码.

I wish to set an attribute on a public property in .NET, however I do not have access to the explicit property itself, as this has been code generated in another file.

我有这个字段:

public virtual string Name { get; set; }

我想设置这个:

[ValidateNonEmpty("Name is required", ExecutionOrder = 1)]
public virtual string Name { get; set; }

我的课程被标记为部分，但你不能有部分属性.我以为我对 MetadataType 类有所了解，这是 Dynamic Data 和 DataAnnotations 的一个新功能，但可惜我觉得它只能与 Dynamic Data 一起使用，这是真的吗?

My class is marked as partial, but you cannot have partial properties. I thought I was on to something with the MetadataType class which is a new feature of Dynamic Data and DataAnnotations, but alas I feel it can only be used with Dynamic Data, is this true?

引用:http://blogs.oosterkamp.nl/blogs/jowen/archive/2008/10/16/metadatatype-attribute.aspxhttp:///blogs.msdn.com/davidebb/archive/2008/06/16/dynamic-data-and-the-associated-metadata-class.aspx

有什么方法可以设置这个属性(甚至通过 web.config！)而不接触代码生成的类?

Is there any way I can set this attributes (even through web.config!) without touching the code generated class?

提前致谢，格雷厄姆

推荐答案

这是一个已知的麻烦；您根本无法将元数据添加到生成的成员中.

This is a known nuisance; you simply can't add metadata to the generated members.

这里有 6 个选项(按努力增加的顺序):

There are 6 options here (in order of increasing effort):

• 如果您拥有该属性，则可以针对类声明它，例如:[ValidateNonEmpty("Name", "Name is required", ExecutionOrder = 1)] - 然后添加部分类定义的多个属性
• 使用虚拟/接口/等方法来查询这个，而不是通过属性来查询
• 子类化生成的类型；覆盖或重新声明成员，添加元数据(真的很乱)
• 使用自定义 TypeDescriptionProvider 来提供动态元数据(大量工作) - 假设消费者尊重 TypeDescriptor；大多数与绑定相关的消费者都会这样做，但例如，Expression(被许多 LINQ 提供程序使用)不会
• 更改代码生成器/编写自己的代码
• 尝试扩展 PostSharp 之类的东西来完成这项工作(我还没有找到方法，但我很想听听你是否找到方法！)

• if you own the attribute, make it possible to declare it against the class, for example: [ValidateNonEmpty("Name", "Name is required", ExecutionOrder = 1)] - then add multiple attributes to the partial class definition
• use a virtual / interface / etc method to query this, rather than via attributes
• sublass the generated type; override or re-declare the member, adding the metadata (really messy)
• use a custom TypeDescriptionProvider to provide dynamic metadata (lots and lots of work) - assuming that the consumer respects TypeDescriptor; most binding-related consumers do, but for example, Expression (used by many LINQ providers) doesn't
• change the code-generator / write your own
• try to extend something like PostSharp to do the work (I haven't found a way to do this, but I've love to hear if you find a way!)

我通常会成功使用第一个选项，除非它是系统定义的属性([DisplayName] 等).如果 [ValidateNonEmpty] 是由动态数据定义的，那么您可能无法做到这一点.

I usually have success with the first option, unless it is a system-defined attribute ([DisplayName], etc). If [ValidateNonEmpty] is defined by dynamic data, then you might not be able to do this.

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