ASP.NET MVC自定義多字段驗證

Question

我正在爲Visual Studio 2015中的驗證開發ASP.NET MVC 5.2.3自定義數據註釋。它需要採取任意數量的字段並確保如果有值，他們都必須有價值;如果它們全部爲空/空白，則應該沒問題。

舉幾個例子幫助：

• ASP.NET MVC implement custom validator use IClientValidatable
• MVC Form Validation on Multiple Fields
• http://www.macaalay.com/2014/02/24/unobtrusive-client-and-server-side-age-validation-in-mvc-using-custom-data-annotations/

但是，我不知道該怎麼辦，你有一個客戶端驗證未知數量的字段被驗證。

您如何通過IClientValidatable接口的GetClientValidationRules()方法的實現將它傳遞給客戶端？

另外，如何將這個新的數據註釋應用到我的視圖模型的屬性？它會是這樣嗎？

[MultipleRequired("AppNumber", "UserId", /* more fields */), ErrorMessage = "Something..."] 
[DisplayName("App #")] 
public int AppNumber { get; set; } 

[DisplayName("User ID")] 
public int UserId { get; set; } 

這裏的，據我可以與MultipleRequiredAttribute自定義數據的註釋類獲得：

public class MultipleRequiredAttribute : ValidationAttribute, IClientValidatable 
{ 
    private readonly string[] _fields; 
    public MultipleRequiredAttribute(params string[] fields) 
    { 
     _fields = fields; 
    } 

    protected override ValidationResult IsValid(object value, ValidationContext validationContext) 
    { 
     // If any field has value, then all must have value 
     var anyHasValue = _fields.Any(f => !string.IsNullOrEmpty(f)); 

     if (!anyHasValue) return null; 

     foreach (var field in _fields) 
     { 
      var property = validationContext.ObjectType.GetProperty(field); 
      if (property == null) 
       return new ValidationResult($"Property '{field}' is undefined."); 

      var fieldValue = property.GetValue(validationContext.ObjectInstance, null); 

      if (string.IsNullOrEmpty(fieldValue?.ToString())) 
       return new ValidationResult(FormatErrorMessage(validationContext.DisplayName)); 
     } 

     return null; 
    } 

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) 
    { 
     yield return new ModelClientValidationRule 
     { 
      ErrorMessage = ErrorMessage, 
      ValidationType = "multiplerequired" 
     }; 
    } 
} 

謝謝。

Answer 1

爲了讓客戶端驗證，則需要通過使用規則的.Add()方法ValidationParameters屬性傳中ModelClientValidationRule的「其他屬性」的值，然後寫客戶端腳本的規則添加到$.validator。

但首先還有一些其他問題需要解決您的屬性。首先，只有在您應用屬性的屬性的值爲null時，才應該執行foreach循環。其次，如果其中一個'其他屬性'不存在，則返回ValidationResult對用戶來說是混淆和無意義的，您應該忽略它。

屬性代碼應爲（注意，我改變了屬性的名稱）

public class RequiredIfAnyAttribute : ValidationAttribute, IClientValidatable 
{ 
    private readonly string[] _otherProperties; 
    private const string _DefaultErrorMessage = "The {0} field is required"; 

    public RequiredIfAnyAttribute(params string[] otherProperties) 
    { 
     if (otherProperties.Length == 0) // would not make sense 
     { 
      throw new ArgumentException("At least one other property name must be provided"); 
     } 
     _otherProperties = otherProperties; 
     ErrorMessage = _DefaultErrorMessage; 
    } 

    protected override ValidationResult IsValid(object value, ValidationContext validationContext) 
    { 
     if (value == null) // no point checking if it has a value 
     { 
      foreach (string property in _otherProperties) 
      { 
       var propertyName = validationContext.ObjectType.GetProperty(property); 
       if (propertyName == null) 
       { 
        continue; 
       } 
       var propertyValue = propertyName.GetValue(validationContext.ObjectInstance, null); 
       if (propertyValue != null) 
       { 
        return new ValidationResult(FormatErrorMessage(validationContext.DisplayName)); 
       } 
      } 
     } 
     return ValidationResult.Success; 
    } 
    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) 
    { 
     var rule = new ModelClientValidationRule 
     { 
      ValidationType = "requiredifany", 
      ErrorMessage = FormatErrorMessage(metadata.GetDisplayName()), 
     }; 
     /pass a comma separated list of the other propeties 
     rule.ValidationParameters.Add("otherproperties", string.Join(",", _otherProperties)); 
     yield return rule; 
    } 
} 

腳本屆時將

sandtrapValidation = { 
    getDependentElement: function (validationElement, dependentProperty) { 
     var dependentElement = $('#' + dependentProperty); 
     if (dependentElement.length === 1) { 
      return dependentElement; 
     } 
     var name = validationElement.name; 
     var index = name.lastIndexOf(".") + 1; 
     var id = (name.substr(0, index) + dependentProperty).replace(/[\.\[\]]/g, "_"); 
     dependentElement = $('#' + id); 
     if (dependentElement.length === 1) { 
      return dependentElement; 
     } 
     // Try using the name attribute 
     name = (name.substr(0, index) + dependentProperty); 
     dependentElement = $('[name="' + name + '"]'); 
     if (dependentElement.length > 0) { 
      return dependentElement.first(); 
     } 
     return null; 
    } 
} 

$.validator.unobtrusive.adapters.add("requiredifany", ["otherproperties"], function (options) { 
    var element = options.element; 
    var otherNames = options.params.otherproperties.split(','); 
    var otherProperties = []; 
    $.each(otherNames, function (index, item) { 
     otherProperties.push(sandtrapValidation.getDependentElement(element, item)) 
    }); 
    options.rules['requiredifany'] = { 
     otherproperties: otherProperties 
    }; 
    options.messages['requiredifany'] = options.message; 
}); 

$.validator.addMethod("requiredifany", function (value, element, params) { 
    if ($(element).val() != '') { 
     // The element has a value so its OK 
     return true; 
    } 
    var isValid = true; 
    $.each(params.otherproperties, function (index, item) { 
     if ($(this).val() != '') { 
      isValid = false; 
     } 
    }); 
    return isValid; 
});