c# - NHibernate - 延迟加载 : no session or session was closed

Question

我对以下 NHibernate 行为感到困惑:
域类和映射:

public class Category
{
    public virtual int ID { get; set; }
    public virtual string Name { get; set; }

    private IList<Product> _products;
    public virtual IList<Product> Products
    {
        get { return new List<Product>(_products).AsReadOnly(); }
    }

    public Category()
    {
        _products = new List<Product>();
    }
}
public class Product
{
    public virtual int ID { get; set; }
    public virtual string Name { get; set; }
    public virtual Category Category { get;set; }
}
public class ProductMap : ClassMap<Product>
{
    public ProductMap()
    {
        Schema("dbo");
        Table("tProducts");

        Id(x => x.ID);
        Map(x => x.Name);
        References(x => x.Category).Column("CategoryID");
    }
}
public class CategoryMap : ClassMap<Category>
{
    public CategoryMap()
    {
        Schema("dbo");
        Table("tCategories");

        Id(x => x.ID);
        Map(x => x.Name);
        HasMany(x => x.Products)
            .KeyColumn("CategoryID")
            .Access.CamelCaseField(Prefix.Underscore)
            .Inverse()
            .Cascade.All();
    }
}

引起问题的代码:

    Category category;

    using (var session = sessionFactory.OpenSession())
    {
        category = session.Get<Category>(1);
    }

    using (var session = sessionFactory.OpenSession())
    {
        var products = category.Products; // exception
    }

为什么我尝试获取产品时没有出现 session 异常？我在这里开会!如何避免这个异常(我在这里更喜欢2个 session ，我想保持懒惰加载)？
提前致谢!

Answer 1

您能否将对象重新附加到您的新 session :

ISession.Update(myDetachedInstance);  

或者，如果对象没有被改变:

ISession.Lock(myDetachedInstance, NHibernate.LockMode.None);  

有关详细信息，请参阅:http://intellect.dk/post/Detached-objects-in-nHibernate-and-Lazy-loading.aspx