使用元数据和实体框架来验证使用数据注释

我有一个名为Product的实体，这是它的声明的一部分:

[EdmEntityTypeAttribute(NamespaceName="NorthwindModel", Name="Product")]
[Serializable()]
[DataContractAttribute(IsReference=true)]
public partial class Product : EntityObject
{
    #region Factory Method
    /// <summary>
    /// Create a new Product object.
    /// </summary>
    /// <param name="productID">Initial value of the ProductID property.</param>
    /// <param name="productName">Initial value of the ProductName property.</param>
    /// <param name="discontinued">Initial value of the Discontinued property.</param>
    public static Product CreateProduct(global::System.Int32 productID, global::System.String productName, global::System.Boolean discontinued)
    {
        Product product = new Product();
        product.ProductID = productID;
        product.ProductName = productName;
        product.Discontinued = discontinued;
        return product;
    }
    #endregion
    #region Primitive Properties
    /// <summary>
    /// No Metadata Documentation available.
    /// </summary>
    [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
    [DataMemberAttribute()]
    public global::System.Int32 ProductID
    {
        get
        {
            return _ProductID;
        }
        set
        {
            if (_ProductID != value)
            {
                OnProductIDChanging(value);
                ReportPropertyChanging("ProductID");
                _ProductID = StructuralObject.SetValidValue(value);
                ReportPropertyChanged("ProductID");
                OnProductIDChanged();
            }
        }
    }
    private global::System.Int32 _ProductID;
    partial void OnProductIDChanging(global::System.Int32 value);
    partial void OnProductIDChanged();
    /// <summary>
    /// No Metadata Documentation available.
    /// </summary>
    [EdmScalarPropertyAttribute(EntityKeyProperty=false, IsNullable=false)]
    [DataMemberAttribute()]
    public global::System.String ProductName
    {
        get
        {
            return _ProductName;
        }
        set
        {
            OnProductNameChanging(value);
            ReportPropertyChanging("ProductName");
            _ProductName = StructuralObject.SetValidValue(value, false);
            ReportPropertyChanged("ProductName");
            OnProductNameChanged();
        }
    }
    private global::System.String _ProductName;
    partial void OnProductNameChanging(global::System.String value);
    partial void OnProductNameChanged();

我想添加数据注释到它的属性。我搜索互联网，并根据这个主题:在实体框架中使用数据注释

我这样创建一个分部类:

[MetadataType(typeof(PersonMetaData))]
public partial class Product
{
}
public class PersonMetaData
{
    [Required(ErrorMessage = "nima", AllowEmptyStrings = false)]
    public global::System.String ProductName { set; get; }
    [Range(minimum: 10, maximum: 100, ErrorMessage = "NIIMMMAA")]
    public global::System.Int32 ProductID { set; get; }
}

，但它不起作用。对于测试，我写以下代码:

using (NorthwindEntities ef=new NorthwindEntities())
        {
            Product p = new Product();
            p.CategoryID = 0;
            p.Discontinued = false;
            p.ProductID = 1000;
            p.ProductName = string.Empty;
            p.QuantityPerUnit = "3";
            p.SupplierID = 3;
            p.UnitsInStock = 0;
            p.UnitsOnOrder = 3;
            var context = new ValidationContext(p, serviceProvider: null, items: null);
            var results = new List<System.ComponentModel.DataAnnotations.ValidationResult>();
            var isValid = Validator.TryValidateObject(p, context, results, true);
            if (!isValid)
            {
                foreach (var validationResult in results)
                {
                    Response.Write(validationResult.ErrorMessage);
                }
            }
        }

，但isValid变量总是为"true"。我错在哪里?

谢谢

public class PersonMetaData
{
    [Required(ErrorMessage = "nima", AllowEmptyStrings = false)]
    public global::System.String ProductName { set; get; }
    [Range(minimum: 10, maximum: 100, ErrorMessage = "NIIMMMAA")]
    public global::System.Int32 ProductID { set; get; }
}

public class PersonMetaData
{
    [Required(ErrorMessage = "nima", AllowEmptyStrings = false)]
    public object ProductName { set; get; }
    [Range(minimum: 10, maximum: 100, ErrorMessage = "NIIMMMAA")]
    public object ProductID { set; get; }
}