Question

是否有基于集合的属性的数据注释验证规则？

我有以下

  <DisplayName("Category")>
  <Range(1, Integer.MaxValue, ErrorMessage:="Please select a category")>
  Property CategoryId As Integer

  <DisplayName("Technical Services")>
  Property TechnicalServices As List(Of Integer)

我正在寻找一个可以添加到TechnicalServices属性的验证器来设置集合大小的最小值。

Answer 1

我认为这样的事情可能有所帮助：

public class MinimumCollectionSizeAttribute : ValidationAttribute
{
    private int _minSize;
    public MinimumCollectionSizeAttribute(int minSize)
    {
        _minSize = minSize;
    }

    public override bool IsValid(object value)
    {
        if (value == null) return true;
        var list = value as ICollection;

        if (list == null) return true;

        return list.Count >= _minSize;
    }    
}

还有改进的余地，但这是一个有效的开始。

Answer 2

.NET 4以后的另一个选择是使类本身（包含有问题的集合属性）实现IValidatableObject，例如：

Public Class SomeClass
  Implements IValidatableObject

  Public Property TechnicalServices() As List(Of Integer)
        Get
            Return m_TechnicalServices
        End Get
        Set
            m_TechnicalServices = Value
        End Set
    End Property
    Private m_TechnicalServices As List(Of Integer)

    Public Function Validate(validationContext As ValidationContext) As IEnumerable(Of ValidationResult)
        Dim results = New List(Of ValidationResult)()

        If TechnicalServices.Count < 1 Then
            results.Add(New ValidationResult("There must be at least one TechnicalService"))
        End If

        Return results
    End Function
End Class

DataAnnotations中的Validator将自动为任何IValidatableObjects调用此Validate方法。

集合的MVC Dataannotation验证规则？

2 个答案: