自定义StringLength验证属性的客户端验证 [英] Client-side validation for custom StringLength validation attribute

问题描述

我具有以下自定义验证属性，该属性是从StringLengthAttribute派生的:

I have the following custom validation attribute, which derives from StringLengthAttribute:

public class StringLengthLocalizedAttribute : StringLengthAttribute
{
    public StringLengthLocalizedAttribute(int maximumLength) : base(maximumLength)
    {
        var translator = DependencyResolver.Current.GetService<ITranslator();
        var translatedValue = translator.Translate("MaxLengthTranslationKey", ErrorMessage);
        ErrorMessage = translatedValue.Replace("{MaxLength}", maximumLength.ToString());
    }
}

此自定义属性的唯一目的是本地化ErrorMessage.问题是，当我在模型中使用它时，它不会生成任何客户端验证，而标准StringLength属性却会生成.

The only purpose of this custom attribute is to localize the ErrorMessage. The problem is, when I use this in my models it does not generate any client-side validation, but the standard StringLength attribute does.

我没有看到我的属性有什么不同-因为它是从StringLength属性派生的，我是否不必实现任何其他功能来使客户端验证正常工作?

I don't see how my attribute differs in any way - since it derives from the StringLength attribute I shouldn't have to implement any additional functionality to get client side validation working?

推荐答案

如果查看DataAnnotationsModelValidatorProvider的源代码，您会在BuildAttributeFactoriesDictionary方法中看到注册了特定类型的属性以进行客户端验证-您已经创建了一种新类型，因此没有客户端验证.

If you look at the source code for DataAnnotationsModelValidatorProvider, you'll see in the method BuildAttributeFactoriesDictionary that specific types of attributes are registered for client side validation - you have created a new type, hence no client side validation.

值得庆幸的是，它还有一个公共方法来添加您自己的适配器，并且在您提供的简单情况下易于使用:

Thankfully, this also has a public method to add your own adapter and is easy to use in the simple case you give:

首先，您需要一个提供客户端验证规则的适配器:

Firstly, you need an adapter that will provide the client validation rules:

public class MyStringLengthAdapter : DataAnnotationsModelValidator<MyStringLengthAttribute>
{
    public MyStringLengthAdapter(ModelMetadata metadata, ControllerContext context, MyStringLengthAttribute attribute)
        : base(metadata, context, attribute)
    {
    }

    public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
    {
        return new[] { new ModelClientValidationStringLengthRule(ErrorMessage, Attribute.MinimumLength, Attribute.MaximumLength) };
    }
}

然后您需要像下面这样在Global.asax.cs的Application_Start方法中注册它:

You then need to register this in the Application_Start method in Global.asax.cs like so:

DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof (MyStringLengthAttribute), typeof (MyStringLengthAdapter));

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