獲取相同類型的多個屬性在MetadataProvider

Question

我有一個屬性，即具有AllowMultiple：

[AttributeUsage(AttributeTargets.Property, AllowMultiple = true)] 
public class AllowedDeviceTypesAttribute : System.Attribute 
{ 
    //... 
} 

，我使用它在我的物業多次：

[AllowedDeviceTypes(DeviceTypes.StaticRegister)] 
[AllowedDeviceTypes(DeviceTypes.MobileRegister)] 
public int ClientNr { get; set; } 

我有一個自定義模型元數據提供程序：

public class ExtendedModelMetadataProvider : DataAnnotationsModelMetadataProvider 
{ 
    protected override ModelMetadata CreateMetadata(IEnumerable<System.Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName) 
    { 
     var attributeList = attributes as IList<System.Attribute> ?? attributes.ToList(); 
     var data = base.CreateMetadata(attributeList, containerType, modelAccessor, modelType, propertyName); 
     //... 
     var allowedDeviceTypesAttributes = attributeList.Where(a => typeof(AllowedDeviceTypesAttribute) == a.GetType()).ToList(); 
     if (allowedDeviceTypesAttributes.Count > 0) 
     { 
      var allowedDeviceTypes = allowedDeviceTypesAttributes.Cast<AllowedDeviceTypesAttribute>().Select(e => e.AllowedDeviceType).ToList(); 
      data.AdditionalValues.Add(AllowedDeviceTypesAttribute.AdditionalMetaDataValue, allowedDeviceTypes); 
     } 

     return data; 
    } 
} 

我的問題是，我總是隻有一個AllowedDeviceTypesAttribute在attributes：

我怎樣才能得到這兩個屬性？

[AllowedDeviceTypes(DeviceTypes.StaticRegister)] 
[AllowedDeviceTypes(DeviceTypes.MobileRegister)] 

Answer 1

爲了使這項工作，我們需要重寫TypeId物業：

[AttributeUsage(AttributeTargets.Property, AllowMultiple = true)] 
public class AllowedDeviceTypesAttribute : System.Attribute 
{ 
    //... 
    public override object TypeId 
    { 
     get 
     { 
      return this; 
     } 
    } 
}