NHibernate.MappingException: No persister for: XYZ

Question

Now, before you say it: I did Google and my hbm.xml file is an Embedded Resource.

Here is the code I am calling:

ISession session = GetCurrentSession();
var returnObject =  session.Get<T>(Id);

Here is my mapping file for the class:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="HQData.Objects.SubCategory, HQData" table="SubCategory" lazy="true">
    <id name="ID" column="ID" unsaved-value="0">
      <generator class="identity" />
    </id>

    <property name="Name" column="Name" />
    <property name="NumberOfBuckets" column="NumberOfBuckets"  />
    <property name="SearchCriteriaOne" column="SearchCriteriaOne" />

    <bag name="_Businesses" cascade="all">
      <key column="SubCategoryId"/>
      <one-to-many 
         class="HQData.Objects.Business, HQData"/>
    </bag>

    <bag name="_Buckets" cascade="all">
      <key column="SubCategoryId"/>
      <one-to-many
         class="HQData.Objects.Bucket, HQData"/>
    </bag>

  </class>
</hibernate-mapping>

Has anyone run to this issue before?

Here is the full error message:

MappingException: No persister for:  HQData.Objects.SubCategory]NHibernate.Impl.SessionFactoryImpl.GetEntityPersister(String entityName, Boolean throwIfNotFound)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Impl\SessionFactoryImpl.cs:766 NHibernate.Impl.SessionFactoryImpl.GetEntityPersister(String entityName)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Impl\SessionFactoryImpl.cs:752 NHibernate.Event.Default.DefaultLoadEventListener.OnLoad(LoadEvent event, LoadType loadType)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Event\Default\DefaultLoadEventListener.cs:37 NHibernate.Impl.SessionImpl.FireLoad(LoadEvent event, LoadType loadType)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Impl\SessionImpl.cs:2054 NHibernate.Impl.SessionImpl.Get(String entityName, Object id)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Impl\SessionImpl.cs:1029 NHibernate.Impl.SessionImpl.Get(Type entityClass, Object id)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Impl\SessionImpl.cs:1020 NHibernate.Impl.SessionImpl.Get(Object id)
 in c:\CSharp\NH2.0.0\nhibernate\src\NHibernate\Impl\SessionImpl.cs:985 HQData.DataAccessUtils.NHibernateObjectHelper.LoadDataObject(Int32 Id)
 in C:\Development\HQChannelRepo\HQ Channel Application\HQChannel\HQData\DataAccessUtils\NHibernateObjectHelper.cs:42 HQWebsite.LocalSearch.get_subCategory()
 in C:\Development\HQChannelRepo\HQ Channel Application\HQChannel\HQWebsite\LocalSearch.aspx.cs:17 HQWebsite.LocalSearch.Page_Load(Object sender, EventArgs e)
 in C:\Development\HQChannelRepo\HQ Channel Application\HQChannel\HQWebsite\LocalSearch.aspx.cs:27 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +33 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +47 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

Update, here's what the solution for my scenario was: I had changed some code and I wasn't adding the Assembly to the config file during runtime.

Answer 1

Sounds like you forgot to add a mapping assembly to the session factory configuration..

If you're using app.config...

.
.
    <property name="show_sql">true</property>
    <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
    <mapping assembly="Project.DomainModel"/>  <!-- Here -->
</session-factory>
.
.