Question

//在部分类中，我试图创建一个自定义的ModelState.IsValid方法。到目前为止，它需要object作为参数，并接收使用validation属性修饰的所有属性值。这很好，但我想从视图中传递方法另一个参数。然后，我可以使用附加值来帮助确定有效性，并可能根据附加值返回自定义消息。

以下是我尝试过的部分类和一些IsValid方法。

[MetadataType(typeof(CS_Parameter_Statewide_AllGrades_ScenarioMetaData))]
public partial class CS_Parameter_Statewide_AllGrades_Scenario
{   
    public int Category { get; set; }

    public class CS_Parameter_Statewide_AllGrades_ScenarioMetaData
    {
        [FormatAttribute] 
        public double Amount { get; set; }
    }

}

public class FormatAttribute : ValidationAttribute, IClientValidatable // IClientValidatable for client side Validation
{
    // this does not work; i don't know how to pass an additional value
    public override bool IsValid(object value, int additonalValue)
    {
        return true;
    }

    // this is what I would like to do
    public override string IsValid(object value, int additonalValue)
    {

        if (additonalValue == 1)
            // validation method 1
            // return message 1
        else if (additonalValue == 2)
            // validation method 2
            // return message 2
        else
            // validation method 3
            // return message 3
    }

    // this is something I was playing with
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {

        var message = "ohoh";
        return new ValidationResult(message);
    }

    // Implement IClientValidatable for client side Validation
    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        return new ModelClientValidationRule[] { new ModelClientValidationRule { ValidationType = "dropdown", ErrorMessage = this.ErrorMessage } };
    }
}

`

Answer 1

您需要一个构造函数来传递属性的名称，该属性的值将包含用于比较和验证的数据。例如

模型

[Format("MyOtherProperty")]
public double Amount { get; set; }

public int MyOtherProperty { get; set; } // the property use to validate

属性

public class FormatAttribute : ValidationAttribute
{
  private readonly string _otherProperty;
  public FormatAttribute(string otherProperty)
  {
    _otherProperty = otherProperty;
  }

  protected override ValidationResult IsValid(object value, ValidationContext validationContext)
  {
    var property = validationContext.ObjectType.GetProperty(_otherProperty);
    if (property == null)
    {
       return new ValidationResult(string.Format("Unknown property: {0}", _otherProperty));
    }
    object otherValue = property.GetValue(validationContext.ObjectInstance, null);
    if (otherValue == someValue) // cast otherValue to correct type
    {
      return new ValidationResult("some error message");
    }
    else if (....)
    {
      return new ValidationResult("another error message");
    }
    return null;
  }
}

Answer 2

您可以创建构造函数并在该构造函数中提供其他字段名称

public class FormatAttribute : ValidationAttribute, IClientValidatable // IClientValidatable for client side Validation
{
private string _additionalAttribute;
  public FormatAttribute(string additionalAttribut)
  {
    _additionalAttribute = additionalAttribut
  }
}

然后在使用ValidationContext的IsValid函数中，您可以检索附加字段的值

 protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        object additionalFieldValue = GetPropertyValue(validationContext.ObjectInstance, _additionalField);
         // Do Logic Here
    }

如何将其他值传递给自定义ModelState.IsValid方法？

2 个答案: