Windows手机创建自定义对象到列？

Question

正如问题标题所示，我正在尝试将自定义对象映射到Windows Phone上的db列，我该怎么做？我得到的例外：＆＃34;无法确定＆＃39;图层的SQL类型。＆＃34;

图层是一个自定义对象，存储这个的正确方法是什么，有人可以请我提供一个示例。谢谢

代码：

...

[Table]
    public class Product : INotifyPropertyChanged, INotifyPropertyChanging
    {
        #region ID
        //not autogenerated, this is from the client
        private String _id;

        [Column(IsPrimaryKey = true, IsDbGenerated = false, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)]
        public String Id
        {
            get { return _id; }
            set
            {
                if (_id != value)
                {
                    NotifyPropertyChanging("id");
                    _id = value;
                    NotifyPropertyChanged("id");
                }
            }
        }

        #endregion

 #region Product Layer
        private Layer _productlayer;

        [Column]
        public Layer ProductLayer
        {
            get { return _productlayer; }
            set
            {
                if (_productlayer != value)
                {
                    NotifyPropertyChanging("ProductLayer");
                    _productlayer = value;
                    NotifyPropertyChanged("ProductLayer");
                }
            }
        }

        #endregion

...

 public class Layer
{
    public string name{ get; set; }
    public string des { get; set; }
    public string pos { get; set; }
}