属性依赖于另一个字段

Question

在我的ASP.NET MVC应用程序的模型中，我希望只有在选中特定复选框时才按需要验证文本框。

喜欢的东西

public bool retired {get, set}; 

[RequiredIf("retired",true)] 
public string retirementAge {get, set}; 

我怎么能这样做？

谢谢。

Answer 1

我还没有看到任何开箱即可以做到这一点。

我创建了一个类供你使用，它有点粗糙，绝对不灵活..但我认为它可以解决你目前的问题。或者至少让你走上正轨。

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.ComponentModel.DataAnnotations; 
using System.Globalization; 

namespace System.ComponentModel.DataAnnotations 
{ 
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)] 
    public sealed class RequiredIfAttribute : ValidationAttribute 
    { 
     private const string _defaultErrorMessage = "'{0}' is required"; 
     private readonly object _typeId = new object(); 

     private string _requiredProperty; 
     private string _targetProperty; 
     private bool _targetPropertyCondition; 

     public RequiredIfAttribute(string requiredProperty, string targetProperty, bool targetPropertyCondition) 
      : base(_defaultErrorMessage) 
     { 
      this._requiredProperty   = requiredProperty; 
      this._targetProperty   = targetProperty; 
      this._targetPropertyCondition = targetPropertyCondition; 
     } 

     public override object TypeId 
     { 
      get 
      { 
       return _typeId; 
      } 
     } 

     public override string FormatErrorMessage(string name) 
     { 
      return String.Format(CultureInfo.CurrentUICulture, ErrorMessageString, _requiredProperty, _targetProperty, _targetPropertyCondition); 
     } 

     public override bool IsValid(object value) 
     { 
      bool result    = false; 
      bool propertyRequired = false; // Flag to check if the required property is required. 

      PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(value); 
      string requiredPropertyValue   = (string) properties.Find(_requiredProperty, true).GetValue(value); 
      bool targetPropertyValue    = (bool) properties.Find(_targetProperty, true).GetValue(value); 

      if (targetPropertyValue == _targetPropertyCondition) 
      { 
       propertyRequired = true; 
      } 

      if (propertyRequired) 
      { 
       //check the required property value is not null 
       if (requiredPropertyValue != null) 
       { 
        result = true; 
       } 
      } 
      else 
      { 
       //property is not required 
       result = true; 
      } 

      return result; 
     } 
    } 
} 

以上模型类，你应该只需要添加：

[RequiredIf("retirementAge", "retired", true)] 
public class MyModel 

在你看来

<%= Html.ValidationSummary() %> 

应显示错误消息每当退役属性为true和所需财产是空的。

希望这会有所帮助。

Answer 2

看看这个：http://blogs.msdn.com/b/simonince/archive/2010/06/04/conditional-validation-in-mvc.aspx

我改装成的代码有点适合我的需要。也许你也从这些改变中受益。

public class RequiredIfAttribute : ValidationAttribute 
{ 
    private RequiredAttribute innerAttribute = new RequiredAttribute(); 
    public string DependentUpon { get; set; } 
    public object Value { get; set; } 

    public RequiredIfAttribute(string dependentUpon, object value) 
    { 
     this.DependentUpon = dependentUpon; 
     this.Value = value; 
    } 

    public RequiredIfAttribute(string dependentUpon) 
    { 
     this.DependentUpon = dependentUpon; 
     this.Value = null; 
    } 

    public override bool IsValid(object value) 
    { 
     return innerAttribute.IsValid(value); 
    } 
} 

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

    public override IEnumerable<ModelClientValidationRule> GetClientValidationRules() 
    { 
     // no client validation - I might well blog about this soon! 
     return base.GetClientValidationRules(); 
    } 

    public override IEnumerable<ModelValidationResult> Validate(object container) 
    { 
     // get a reference to the property this validation depends upon 
     var field = Metadata.ContainerType.GetProperty(Attribute.DependentUpon); 

     if (field != null) 
     { 
      // get the value of the dependent property 
      var value = field.GetValue(container, null); 

      // compare the value against the target value 
      if ((value != null && Attribute.Value == null) || (value != null && value.Equals(Attribute.Value))) 
      { 
       // match => means we should try validating this field 
       if (!Attribute.IsValid(Metadata.Model)) 
        // validation failed - return an error 
        yield return new ModelValidationResult { Message = ErrorMessage }; 
      } 
     } 
    } 
} 

然后使用它：

public DateTime? DeptDateTime { get; set; } 
[RequiredIf("DeptDateTime")] 
public string DeptAirline { get; set; } 

Answer 3

试试我的自定义validation attribute：

[ConditionalRequired("retired==true")] 
public string retirementAge {get, set}; 

它支持多个条件。

Answer 4

只需使用万无一失的验证库，在CodePlex上： https://foolproof.codeplex.com/

支持，除其他外，下面的“requiredif”确认属性/装饰品：

[RequiredIf] 
[RequiredIfNot] 
[RequiredIfTrue] 
[RequiredIfFalse] 
[RequiredIfEmpty] 
[RequiredIfNotEmpty] 
[RequiredIfRegExMatch] 
[RequiredIfNotRegExMatch] 

上手容易：

1. 从提供的链接下载软件包
2. 添加对包含的.dll文件的引用
3. 导入包含的JavaScript文件
4. 确保您的视图在其HTML中引用包含的JavaScript文件，以实现不显眼的javascript和jquery验证。

Answer 5

使用NuGet包管理器我intstalled这样的：https://github.com/jwaliszko/ExpressiveAnnotations

这是我的模型：

using ExpressiveAnnotations.Attributes; 

public bool HasReferenceToNotIncludedFile { get; set; } 

[RequiredIf("HasReferenceToNotIncludedFile == true", ErrorMessage = "RelevantAuditOpinionNumbers are required.")] 
public string RelevantAuditOpinionNumbers { get; set; } 

我向你保证，这将工作！