C#字符串枚举作为NHibernate鉴别器
本文关键字:NHibernate 鉴别 字符串 枚举 | 更新日期: 2023-09-27 18:20:29
我有一个案例不能真正开始工作。基本上,我有抽象类User
和扩展类Admin
、Teacher
和LabEmployee
。以下是我的映射:
<class name="User" table="users" dynamic-update="true" dynamic-insert="true" select-before-update="false">
<id name="Id">
<column name="id" sql-type="bigint"/>
<generator class="identity"/>
</id>
<discriminator column="user_type" type="String"/>
...
some irrelevant properties (username, password, email etc.)
...
<subclass name="Admin" discriminator-value="ADMIN"/>
<subclass name="LabEmloyee" discriminator-value="LABEMPLOYEE"/>
<subclass name="Teacher" discriminator-value="TEACHER"/>
</class>
现在,我真的很想使用这个Enum
public enum UserType
{
ADMIN, LABEMPLOYEE, TEACHER
}
我知道Nhibernate默认情况下会将枚举映射为整数,因此ADMIN将为"0",LABEMPLOYEE将为"1",TEACHER将为"2"。我试着关注这个帖子:
http://codebetter.com/jefferypalermo/2006/03/14/using-enum-strings-with-nhibernate-persistence-level-400/
并定义了UserTypeWrapper:
public class UserTypeWrapper: NHibernate.Type.EnumStringType
{
public UserTypeWrapper()
: base(typeof(User.UserType))
{
}
}
但它假设enum不是鉴别器,也就是说,我不能将鉴别器类型设置为UserTypeWrapper
,因为NHibernate抛出MappingException"Cannot determine type for:UserTypeWrapper"。
有人知道如何做到这一点吗?
如有任何帮助,我们将不胜感激!谢谢
鉴别器值在类中找不到,因此您不需要任何用户类型来从db转换为property。在hbm中,您也不能使用enum,您必须直接在discriminator-value=""
中写入值。你想要的可能是:
abstract class User
{
public virtual UserType Type { get; protected set;}
}
class Teacher : User
{
public Teacher()
{
Type = UserType.Teacher;
}
}
class LabEmployee : User
{
public LabEmployee()
{
Type = UserType.LabEmployee;
}
}
switch(someuser.Type)
或使用常规
abstract class User
{
public virtual UserType Type { get; protected set;}
public User()
{
Type = Enum.Parse(typeof(UserType), this.GetType().Name);
}
}
并使用映射中值的约定(Fluent NHibernate约定指定鉴别器值)
public class DiscriminatorValueConvention : ISubclassConvention
{
public void Apply(ISubclassInstance instance)
{
instance.DiscriminatorValue(instance.EntityType.Name);
}
}