Question

我正在尝试使用WCF通过线路发送NH实体。我有一个懒惰加载对象的复杂图表.. 我尝试在序列化时实现自定义DataContractSurrogate以强制初始化。这是代码：

public class HibernateDataContractSurrogate : IDataContractSurrogate
{
    public HibernateDataContractSurrogate()
    {
    }

    public Type GetDataContractType(Type type)
    {
        // Serialize proxies as the base type
        if (typeof(INHibernateProxy).IsAssignableFrom(type))
        {
            type = type.GetType().BaseType;
        }

        // Serialize persistent collections as the collection interface type
        if (typeof(IPersistentCollection).IsAssignableFrom(type))
        {
            foreach (Type collInterface in type.GetInterfaces())
            {
                if (collInterface.IsGenericType)
                {
                    type = collInterface;
                    break;
                }
                else if (!collInterface.Equals(typeof(IPersistentCollection)))
                {
                    type = collInterface;
                }
            }
        }

        return type;
    }

    public object GetObjectToSerialize(object obj, Type targetType)
    {
        if (obj is INHibernateProxy)
        {
            obj = ((INHibernateProxy)obj).HibernateLazyInitializer.GetImplementation();
        }

        // Serialize persistent collections as the collection interface type
        if (obj is IPersistentCollection)
        {
            IPersistentCollection persistentCollection = (IPersistentCollection)obj;
            persistentCollection.ForceInitialization();
            obj = persistentCollection.Entries(null); // This returns the "wrapped" collection
        }

        return obj;
    }

    public object GetDeserializedObject(object obj, Type targetType)
    {
        return obj;
    }

    public object GetCustomDataToExport(MemberInfo memberInfo, Type dataContractType)
    {
        return null;
    }

    public object GetCustomDataToExport(Type clrType, Type dataContractType)
    {
        return null;
    }

    public void GetKnownCustomDataTypes(Collection<Type> customDataTypes)
    {
    }

    public Type GetReferencedTypeOnImport(string typeName, string typeNamespace, object customData)
    {
        return null;
    }

    public CodeTypeDeclaration ProcessImportedType(CodeTypeDeclaration typeDeclaration, CodeCompileUnit compileUnit)
    {
        return typeDeclaration;
    }
}

但是，我一直有例外：

NHibernate.Exceptions.GenericADOException: could not initialize a collection [SQL trace] ---> System.ObjectDisposedException: Session is closed!

查看堆栈跟踪，看来此行persistentCollection.ForceInitialization(); 抛出异常。

我该怎么办？

PS：我想使用DTO而不是序列化复杂的NH实体，但这里不可能。

Answer 1

在关闭加载它的NHibernate.ISession对象后，您无法延迟加载集合。您拥有的唯一选择是：

保持ISession打开，直到您序列化数据。
关闭延迟加载。
确保在关闭会话之前获取所有延迟加载的集合。

Answer 2

在此处查看答案：What are the problems associated with sending a Hibernate Proxy class to clients

NHibernate使用WCF序列化延迟加载的实体

2 个答案: