获取作为字符串传入的属性的值

Question

我正在尝试创建一个自定义验证,说"如果otherValue为true,那么这个值必须大于0.我能够获得值,但是我现在设置了otherValue的方式,我只有属性的名称,而不是值.可能是因为它作为一个字符串传入.这个属性将在5或6个不同的属性上,每次,它将调用一个不同的otherValue.寻求有关如何获取的属性的帮助otherValue的实际值(它是一个bool).

这是我目前的代码:

public class MustBeGreaterIfTrueAttribute : ValidationAttribute, IClientValidatable
{
    // get the radio button value
    public string OtherValue { get; set; }

    public override bool IsValid(object value)
    {
        // Here is the actual custom rule
        if (value.ToString() == "0")
        {
            if (OtherValue.ToString() == "true")
            {
                return false;
            }
        }
        // If all is ok, return successful.
        return true;
    }

======================编辑=========================

这就是我现在所处的位置,它的确有效!现在我需要参考如何制作它,以便在模型中添加属性时可以放入不同的errorMessage:

public class MustBeGreaterIfTrueAttribute : ValidationAttribute, IClientValidatable
{
    // get the radio button value
    public string OtherProperty { get; set; }

    protected override ValidationResult IsValid(object value, ValidationContext context)
    {
        var otherPropertyInfo = context.ObjectInstance.GetType();
        var otherValue = otherPropertyInfo.GetProperty(OtherProperty).GetValue(context.ObjectInstance, null);      

        // Here is the actual custom rule
        if (value.ToString() == "0")
        {
            if (otherValue.ToString().Equals("True", StringComparison.InvariantCultureIgnoreCase))
            {
                return new ValidationResult("Ensure all 'Yes' answers have additional data entered.");
            }
        }
        // If all is ok, return successful.
        return ValidationResult.Success;
    }

    // Add the client side unobtrusive 'data-val' attributes
    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        var rule = new ModelClientValidationRule();
        rule.ValidationType = "requiredifyes";
        rule.ErrorMessage = this.ErrorMessage;
        rule.ValidationParameters.Add("othervalue", this.OtherProperty);
        yield return rule;
    }

}

所以我应该能够做到这一点:

    [MustBeGreaterIfTrue(OtherProperty="EverHadRestrainingOrder", ErrorMessage="Enter more info on your RO.")]
    public int? ROCounter { get; set; }

Answer 1

该ValidationAttribute有一对IsValid方法和您的方案,你必须用其他的家伙.

  public class MustBeGreaterIfTrueAttribute : ValidationAttribute
  {
    // name of the OtherProperty. You have to specify this when you apply this attribute
    public string OtherPropertyName { get; set; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
      var otherProperty = validationContext.ObjectType.GetProperty(OtherPropertyName);

      if (otherProperty == null)
        return new ValidationResult(String.Format("Unknown property: {0}.", OtherPropertyName));

      var otherPropertyValue = otherProperty.GetValue(validationContext.ObjectInstance, null);

      if (value.ToString() == "0")
      {
        if (otherPropertyValue != null && otherPropertyValue.ToString() == "true")
        {
          return null;
        }
      }

      return new ValidationResult("write something here");
    }
  }

用法示例:

public class SomeModel
{
    [MustBeGreaterIf(OtherPropertyName="Prop2")]
    public string Prop1 {get;set;}
    public string Prop2 {get;set;}
}

参考:http://www.concurrentdevelopment.co.uk/blog/index.php/2011/01/custom-validationattribute-for-comparing-properties/