流利的NHibernate的错误：实体“ClassMap`1”不具有标识映射 [英] Fluent NHibernate error: The entity 'ClassMap`1' doesn't have an Id mapped

问题描述

我使用到功能NHibernate正常的NHibernate的hbm.xml映射转换previous项目。目前，我卡在什么应该是最后一个步骤，以得到这个工作之一。我添加了一个派生类DefaultAutomappingConfiguration修改我的ID命名约定。字符串ID追加到类名称：

I'm converting a previous project from using normal NHibernate hbm.xml mappings to Fluent NHibernate. Currently, I'm stuck on what should be one of the last steps to getting this working. I've added a derived class for DefaultAutomappingConfiguration to modify my ID naming convention. The string "Id" is appended to the class name:

    public override bool IsId(FluentNHibernate.Member member)
    {
        return member.Name == member.DeclaringType.Name + "Id";
    }

这应该使局有一个ID在一个名为AgencyId字段。相反，我得到这个错误：

This should make "Agency" have an ID in a field named "AgencyId". Instead, I'm getting this error:

The entity 'ClassMap`1' doesn't have an Id mapped. Use the Id method to map your identity property. For example: Id(x => x.Id).
{Name = "ClassMap`1" FullName = "FluentNHibernate.Mapping.ClassMap`1[[BackendDb.Model.Agency, BackendDb, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]"}

我做了一个断点上ISID功能，看看发生了什么：

I made a breakpoint on the IsId function to see what's going on:

{Property: Cache}
{Name = "ClassMap`1" FullName = "FluentNHibernate.Mapping.ClassMap`1[[BackendDb.Model.Agency, BackendDb, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]"}

这是什么？对象是不是我已经创建。每隔对象通过这个功能很好，和那些我其实是想映射正在返回正确的值。

What is this? The object is not something I've created. Every other object passes through this function fine, and the ones I actually wanted to map are returning the proper value.

我的会话工厂看起来是这样的：

My Session factory looks something like this:

var cfg = new MapConfig();
return Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2008
.ConnectionString(m => m.Server(@".\SqlExpress")
    .Database("{some dbname}")
    .TrustedConnection()))
.Mappings(m =>
    m.AutoMappings
        .Add(AutoMap.AssemblyOf<Agency>(cfg))
)
.BuildSessionFactory();

烦人，似乎这在某种程度上造成了三桌，我在测试功能NHibernate在我的开发数据库是清空。什么玩意？

推荐答案

SessionFactory则是试图自动映射中的所有类，其中包含基于该指令的代理类的程序集：添加（AutoMap.AssemblyOf＆LT;机构＆GT;（CFG））。既然你有一个 AgencyMap 在装配和 ClassMap＆LT;＆GT; 不具有标识属性，FNH是抛出一个错误。

The sessionfactory is trying to automap all classes in the assembly that contains your Agency class based on this directive: Add(AutoMap.AssemblyOf<Agency>(cfg)). Since you have an AgencyMap in the assembly andClassMap<> does not have an Id property, FNH is throwing an error.

如果你想使用 ClassMap＆LT;＆GT; 配置，而不​​是（或补充）宣布的自动映射配置，声明流利的映射：

If you want to use ClassMap<> configurations, instead of (or in addition to) declaring an automapping configuration, declare a fluent mapping:

m.FluentMappings.AddFromAssemblyOf<Agency>();

如果您不需要AutoMappings，删除`.AutoMappings.Add'指令。

If you don't need AutoMappings, remove the `.AutoMappings.Add' directive.

不过，如果你想使用AutoMappings，你需要告诉FNH你想要什么类映射。为了解决这个问题，我通常会定义一个标记接口：

However, if you want to use AutoMappings, you need to tell FNH what classes you want to map. To handle this, I usually define a marker interface:

public abstract class Entity : IPersistable
{
    public virtual int Id { get; set; }
}

public interface IPersistable
{
}

然后，我从 DefaultAutomappingConfiguration 派生类的，我告诉FNH只图有该接口的类（你可以限制映射类，但是你认为合适的）：

Then, in the class that I derive from DefaultAutomappingConfiguration, I tell FNH to only map the classes that have that interface (you can limit the mapped classes however you see fit):

public class EntityAutoMappingConfiguration : DefaultAutomappingConfiguration
{
    public override bool ShouldMap(Type type)
    {
        return type.GetInterfaces().Contains(typeof (IPersistable));
    }

}

要处理的主键映射，我创建了一个约定类：

To handle the primary key mapping, I create a convention class:

public class PrimaryKeyNamePlusId : IIdConvention 
{
    public void Apply(IIdentityInstance instance)
    {
        instance.Column(instance.EntityType.Name+"Id");
    }
}

最后，配置我的SessionFactory使用的配置/会展类：

Finally, I configure my SessionFactory to use the configuration/convention classes:

 m.AutoMappings.AssemblyOf<Entity>(new EntityAutoMappingConfiguration())
            .IgnoreBase<Entity>()
            .UseOverridesFromAssemblyOf<Entity>()
            .Conventions.AddFromAssemblyOf<Entity>();

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