问类级别和属性级别上的ASP.Net MVC 2自定义属性可以同时激活吗？

EN

[IsCityInCountry("CountryID", "CityID"]
public class UserInfo
{
    [Required]
    public int UserID { get; set; }

    [Required]
    public int CountryID { get; set; }

    [Required]
    public int CityID { get; set; }
}

using System;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

[AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
public class IsCityInCountry : ValidationAttribute
{
    public IsCityInCountry(string countryIDProperty, string cityIDProperty)
    {
        CountryIDProperty = countryIDProperty;
        CityIDProperty = cityIDProperty;
    }
    public string CountryIDProperty { get; set; }
    public string CityIDProperty { get; set; }

    public override bool IsValid(object value)
    {
        var properties = TypeDescriptor.GetProperties(value);

        var countryID = properties.Find(CountryIDProperty, true).GetValue(value);
        var cityID = properties.Find(CityIDProperty , true).GetValue(value);

        int countryIDInt;
        int.TryParse(countryID.ToString(), out countryIDInt);

        int cityIDInt;
        int.TryParse(cityID.ToString(), out cityIDInt);

        if (CountryBusiness.IsCityInCountry(countryIDInt, cityIDInt))
        {
            return true;
        }

        return false;
    }
}