寻找从ClassMap<主键; T> [英] Finding the Primary Key from a ClassMap<T>
问题描述
使用功能NHibernate
,我有一个任意 ClassMap< T>
,我希望能够找出什么属性(如果有的话)被设置为主键
例如:
公共类PersonMap:ClassMap<&人GT;
{
公共PersonMap()
{
编号(P => p.StupidPrimaryKeyId).GeneratedBy.Identity()列(StupidPrimaryKeyId);
}
}
...
//使用
的MemberInfo primaryKeyMember = FindPrimaryKey(新PersonMap());
谁能告诉我什么方法体 FindPrimaryKey
将不得不为了回报 StupidPrimaryKeyId
编辑:12年1月10日
我本来想这是因为我想知道在数据库中是否不存在一个独立的实体,完全基于主键(因此我需要知道主键成员,而不是字符串)。我将沿着这条道路,因为很多这样的代码,在我们的代码基础已经存在。重新思考这个问题之后,我反而意识到映射应该已经采取照顾,因此,使用NHibernate.Linq我知道有这样的:
公共虚拟BOOL RecordExists(TRecord OBJ)
{
变种存在= _session.Query< TRecord>()式(R => R == OBJ)。任何();
收益存在虚假==;
}
所以...我检查流利,NHibernate的
与反射
DLL和这是我来到-了:
公共字符串FindPrimaryKey< T>(ClassMap< T>图)
{
VAR providersInfo = map.GetType()BaseType.GetField。 (供应商,BindingFlags.Instance | BindingFlags.NonPublic可);
VAR providersValue =(MappingProviderStore)providersInfo.GetValue(图)
变种n = providersValue.Id
VAR PKName =((名单<字符串方式>)Id.GetType()getfield命令(列,BindingFlags.Instance | BindingFlags.NonPublic可)
.GetValue (ID))的SingleOrDefault();
返回PKName;
}
按viggity修改
这是我真的很期待的。 !再次感谢
public成员FindPrimaryKey< T>(ClassMap< T>图)
{
变种providersInfo = map.GetType()BaseType.GetField(供应商,BindingFlags.Instance | BindingFlags.NonPublic可)。
VAR providersValue =(MappingProviderStore)providersInfo.GetValue(图)
VAR ID = providersValue.Id;
VAR pkMemberInfo =(会员)id.GetType()getfield命令(成员,BindingFlags.Instance | BindingFlags.NonPublic可).GetValue(ID)。
返回pkMemberInfo;
}
最终修改
PKName(如果明确指定了列名)将获得StupidPrimaryKeyId列名。
我必须说,我很好奇,知道为什么你需要它。
With Fluent NHibernate
, I have an arbitrary ClassMap<T>
, I want to be able to find out what property (if any) was set as the primary key
.
Example:
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Id(p => p.StupidPrimaryKeyId).GeneratedBy.Identity().Column("StupidPrimaryKeyId");
}
}
...
//usage
MemberInfo primaryKeyMember = FindPrimaryKey(new PersonMap());
Can anybody tell me what the method body for FindPrimaryKey
would have to be in order to return StupidPrimaryKeyId
?
Edit: 1/10/12
I originally wanted this because I wanted to know whether or not a detached entity existed in the database, based solely on the primary key (thus my need for knowing the primary key member, not string). I set down this path because a lot of this code already existed in our code base. After rethinking the issue, I've instead realized that the mapping should already take care of that, so using NHibernate.Linq I know have this:
public virtual bool RecordExists(TRecord obj)
{
var exists = _session.Query<TRecord>().Where(r => r == obj).Any();
return exists == false;
}
So... I inspected Fluent-Nhibernate
dll with Reflector
and this is what I came-up with:
public string FindPrimaryKey<T>(ClassMap<T> map)
{
var providersInfo = map.GetType().BaseType.GetField("providers", BindingFlags.Instance | BindingFlags.NonPublic);
var providersValue = (MappingProviderStore) providersInfo.GetValue(map);
var Id = providersValue.Id
var PKName = ((List<string>) Id.GetType().GetField("columns", BindingFlags.Instance | BindingFlags.NonPublic)
.GetValue(Id)).SingleOrDefault();
return PKName;
}
Edit by viggity
This is what I was really looking for. Thanks again!
public Member FindPrimaryKey<T>(ClassMap<T> map)
{
var providersInfo = map.GetType().BaseType.GetField("providers", BindingFlags.Instance | BindingFlags.NonPublic);
var providersValue = (MappingProviderStore) providersInfo.GetValue(map);
var id = providersValue.Id;
var pkMemberInfo = (Member)id.GetType().GetField("member", BindingFlags.Instance | BindingFlags.NonPublic).GetValue(id);
return pkMemberInfo;
}
end edit
PKName (if the column name assigned explicitly) will obtain the "StupidPrimaryKeyId" column name.
I must say that I'm curious to know why do you need it.
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