我遇到了一个场景，我需要知道哪个属性是目前正在定制 ValidationAttribute 验证。我以为这会很容易在MVC 3，因为 ValidationContext 被传递到的 的IsValid 的方法。

I ran into a scenario where I needed to know which property was currently being validated in a custom ValidationAttribute. I assumed this would be easy in MVC 3 since the ValidationContext is being passed into the IsValid method.

没有进入细节，这里的基本思想是：

Without going into detail, here is the basic idea:

protected override ValidationResult IsValid(Object value, ValidationContext validationContext) {

   if (ShouldICareAboutYou(validationContext.MemberName))
   {
       //Do some stuff
   }

   //Return the results
}

这似乎像是一个完美的解决方案，而事实上，在单元测试我的自定义ValidationAttribute使用Validator.TryValidateObject一切都一级棒！

This seemed like the perfect solution, and indeed, when unit testing my custom ValidationAttribute using Validator.TryValidateObject everything worked beautifully!

但是...

在调用TryUpdateModel,或TryValidateModel在我的控制器，验证运行，但 ValidationContext.MemberName 为空。

Whaa咦？！？

我做了一个小调查，果然，就在那里里面DataAnnotationsModelValidator是code ...或缺乏。

I did a little investigation and sure enough, right there inside of DataAnnotationsModelValidator is the code... or lack thereof.

public override IEnumerable<ModelValidationResult> Validate(object container) {
    // Per the WCF RIA Services team, instance can never be null (if you have
    // no parent, you pass yourself for the "instance" parameter).
    ValidationContext context = new ValidationContext(container ?? Metadata.Model, null, null); 
    context.DisplayName = Metadata.GetDisplayName();

    // Setting the MemberName here would be trivial!
    // However, philh told me not to. Something about
    // a guy named Josh who pushed him down on the playground
    // in middle school.

    //context.MemberName = Metadata.PropertyName; (Suck It, Josh!!!)

    ValidationResult result = Attribute.GetValidationResult(Metadata.Model, context); 
    if (result != ValidationResult.Success) {
        yield return new ModelValidationResult { 
            Message = result.ErrorMessage
        };
    }
} 

我知道显示名称的可以的是属性名，如果没有 DisplayAttribute 已施加到属性。不幸的是我真的不能买卖hypotheticals。我需要知道的完全什么是属性名称是。

I realize that DisplayName could be the property name if no DisplayAttribute has been applied to the property. Unfortunately I can't really deal in hypotheticals. I need to know exactly what the property name is.

那么，什么是交易？这是由设计或一个诚实的监督如果这是一个疏忽，那么这将是真棒得到这个固定的MVC 4：。）

So what is the deal? Is this by design or an honest oversight. If it is an oversight, then it would be awesome to get this fixed in MVC 4 :)

在加入的的code样品上方意在评论很好玩。我不知道，我也没有见过菲尔哈克。从我可以告诉他似乎是一个真正的好人。而把他倒在初中就已经让我皇室冲洗！

The added comments in the code sample above are meant to be funny. I do not know, nor have I ever met Phil Haack. From what I can tell he seems like a really nice guy. And pushing him down in middle school would have made me a royal douche!

推荐答案

我有同样的问题，并决定在属性名传递作为属性构造函数的参数，然后将其存储在属性。例如：

I had this same problem and decided to pass in the property name as a parameter in the attribute constructor and then store it in the attribute. For example:

[MyValidationAttribute("MyProperty")]
public string MyProperty { get; set; }

然后在MyValidationAttribute.cs：

Then in MyValidationAttribute.cs:

public class MyValidationAttribute
{
    private string PropertyName;

    public MyValidationAttribute(string propertyName)
    {
        this.PropertyName = propertyName;
    }
}

这是一个有点讨厌，现在我必须键入我的财产的名字两次，但它解决了这个问题。

It is a little annoying that now I have to type the name of my property twice but it solves the problem.