为了使一切都能很好地与新的不显眼的验证相结合,您需要做一些事情.几个星期前我通过它们.

首先,创建一个继承自ValidationAttribute的自定义属性类.一个简单的requiredIf属性类如下：

Imports System.ComponentModel
Imports System.ComponentModel.DataAnnotations

<AttributeUsage(AttributeTargets.Field Or AttributeTargets.Property,AllowMultiple:=False,Inherited:=False)> _
Public NotInheritable Class requiredIfAttribute
    Inherits ValidationAttribute

    Private Const    _defaultErrorMessage As String = "'{0}' is required."
    Private ReadOnly _dependentProperty   As String
    Private ReadOnly _targetValues        As Object()

    Public Sub New(dependentProperty As String,targetValues As Object())

        MyBase.New(_defaultErrorMessage)

        _dependentProperty = dependentProperty
        _targetValues      = targetValues

    End Sub

    Public Sub New(dependentProperty As String,targetValues As Object(),errorMessage As String)

        MyBase.New(errorMessage)

        _dependentProperty = dependentProperty
        _targetValues      = targetValues

    End Sub

    Public ReadOnly Property DependentProperty() As String
        Get
            Return _dependentProperty
        End Get
    End Property

    Public ReadOnly Property TargetValues() As Object()
        Get
            Return _targetValues
        End Get
    End Property

    Public Overrides Function FormatErrorMessage(name As String) As String

        Return String.Format(Globalization.CultureInfo.CurrentUICulture,ErrorMessageString,name)

    End Function

    Protected Overrides Function IsValid(value As Object,context As ValidationContext) As ValidationResult

        ' find the other property we need to compare with using reflection
        Dim propertyValue = context.ObjectType.GetProperty(DependentProperty).GetValue(context.ObjectInstance,Nothing).ToString()

        Dim match = TargetValues.SingleOrDefault(Function(t) t.ToString().ToLower() = propertyValue.ToLower())

        If match IsNot Nothing AndAlso value Is Nothing Then
            Return New ValidationResult(FormatErrorMessage(context.DisplayName))
        End If

        Return Nothing

    End Function

End Class

接下来,您需要实现验证器类.该类负责让MVC知道不显眼的验证库工作所需的客户端验证规则.

Public Class requiredIfValidator
    Inherits DataAnnotationsModelValidator(Of requiredIfAttribute)

    Public Sub New(MetaData As ModelMetadata,context As ControllerContext,attribute As requiredIfAttribute)

        MyBase.New(MetaData,context,attribute)

    End Sub

    Public Overrides Function GetClientValidationRules() As IEnumerable(Of ModelClientValidationRule)

        Dim rule As New ModelClientValidationRule() With {.ErrorMessage = ErrorMessage,.ValidationType = "requiredif"}

        rule.ValidationParameters("dependentproperty") = Attribute.DependentProperty.Replace("."c,HtmlHelper.IdAttributeDotReplacement)

        Dim first       As Boolean = True
        Dim arrayString As New StringBuilder()

        For Each param In Attribute.TargetValues
            If first Then
                first = False
            Else
                arrayString.Append(",")
            End If
            arrayString.Append(param.ToString())
        Next

        rule.ValidationParameters("targetvalues") = arrayString.ToString()

        Return New ModelClientValidationRule() {rule}

    End Function

End Class

现在,您可以在Global.asax的应用程序启动方法中注册所有内容：

DataAnnotationsModelValidatorProvider.RegisterAdapter(GetType(requiredIfAttribute),GetType(requiredIfValidator))

这可以让你90％的方式.现在您只需要告诉JQuery validate和MS不显眼的验证层如何读取您的新属性：

/// <reference path="jquery-1.4.1-vsdoc.js" />
/// <reference path="jquery.validate-vsdoc.js" />

/* javascript for custom unobtrusive validation
   ==================================================== */

(function ($) {

    // this adds the custom "requiredif" validator to the jQuery validate plugin
    $.validator.addMethod('requiredif',function (value,element,params) {

                              // the "value" variable must not be empty if the dependent value matches
                              // one of the target values
                              var dependentVal = $('#' + params['dependentProperty']).val().trim().toLowerCase();
                              var targetValues = params['targetValues'].split(',');

                              // loop through all target values
                              for (i = 0; i < targetValues.length; i++) {
                                  if (dependentVal == targetValues[i].toLowerCase()) {
                                      return $.trim(value).length > 0;
                                  }
                              }

                              return true;
                          },'not used');

    // this tells the MS unobtrusive validation layer how to read the
    // HTML 5 attributes that are output for the custom "requiredif" validator
    $.validator.unobtrusive.adapters.add('requiredif',['dependentProperty','targetValues'],function (options) {

        options.rules['requiredif'] = options.params;
        if (options.message) {
            options.messages['requiredif'] = options.message;
        }

    });

} (jQuery));

希望这会有所帮助,这对于工作来说真的很痛苦.