c# - Validator.TryValidateProperty 不工作

Question

我正在尝试实现 Validator.TryValidateProperty，即使存在 [Required] DataAnnotation，TryValidateProperty 也会返回有效响应。

这是我的客户部分类:

[MetadataType(typeof(Customer.Metadata))]
public partial class Customer : global::System.Data.Objects.DataClasses.EntityObject 
{
   ...
private sealed class Metadata
    {

        [Required]
        [SSNValidAttribute(ErrorMessage = "The SSN should be 9 numeric characters without any punctuation.")]
        [DisplayName("SSN")]
        public String SSN { get; set; }
...

这是返回 True 的代码:

...
var customer = new Customer();
            customer.SSN = "";
            var vc = new ValidationContext(customer, null, null);
            vc.MemberName = "SSN";
            var res = new List<ValidationResult>();
            var result = Validator.TryValidateProperty(customer.SSN, vc, res);
...

Answer 1

好的，刚刚找到了处理密封的 MetadataType 类的解决方案。

var customer = new Customer();
TypeDescriptor.AddProviderTransparent
(new AssociatedMetadataTypeTypeDescriptionProvider
    (customer.GetType()), customer.GetType());
customer.SSN = "";
var vc = new ValidationContext(customer, null, null);
vc.MemberName = "SSN";
var res = new List<ValidationResult>();
var result = Validator.TryValidateProperty(customer.SSN, vc, res);

我必须添加以下内容:

TypeDescriptor.AddProviderTransparent
(new AssociatedMetadataTypeTypeDescriptionProvider
    (customer.GetType()), customer.GetType());

在此地址找到解决方案: http://forums.silverlight.net/forums/p/149264/333396.aspx