Unable to cast object of type 'NHibernate.Collection.PersistentBag' to type 'ApplicationFramework.BE.Collections.CaseGroupCollection'.

When I use ILIST rather the way I have written above no issue for me. But whenever I use my own userCollection (CaseGroupCollection), I am facing this error.

This is very urgent and I refered in the forum it says to refer another link."http://sourceforge.net/mailarchive/".
I could not find specific help, as it is running through morethan 1000s mails. Kindly spare sometime to help me on this, as it very urgent to me for my application. Whoever came across and solved please pen down your valuable suggestions.

Hibernate version: 1.2

Source Code for my Entity:

Declaration:

protected int caseSetId = 0;
protected string caseSetName = null;
protected string setDescription = null;
protected CaseGroupCollection caseGroups = null;

Property:

public virtual CaseGroupCollection CaseGroups
{
get
{
return caseGroups;
}
set
{
string fullyQualifiedPropertyName = this.GetType().ToString() + "." + Property.CaseGroups.ToString();
caseGroups_IsChanged = caseGroups != value;

if (caseGroups != value)
{
caseGroups = value; if(caseGroups != caseGroups_InitialValue)
{
if (!dirtyProperties.Contains("CaseGroups"))
{
dirtyProperties.Add("CaseGroups");
}
}
else
{
if (dirtyProperties.Contains("CaseGroups"))
{
dirtyProperties.Remove("CaseGroups");
}
}
}
}
}


Mapping documents:
<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="ApplicationFramework.BE.CaseSet, ApplicationFramework" table="CM_CASE_SET">
<id name="CaseSetId" type="Int32" unsaved-value="null">
<column name="CASE_SET_ID" length="4" sql-type="int" not-null="true" />
<generator class="assigned" />
</id>
<property name="CaseSetName" type="String">
<column name="CASE_SET_NAME" length="200" sql-type="varchar" not-null="true" />
</property>
<property name="SetDescription" type="String">
<column name="SET_DESCRIPTION" length="1500" sql-type="varchar" not-null="false" />
</property>
</property>
<bag name="CaseGroups" inverse="true" lazy="true" cascade="all-delete-orphan" generic="false">
<key column="CASE_SET_ID" />
<one-to-many class="ApplicationFramework.BE.CaseGroup, ApplicationFramework" />
</bag>
</class>
</hibernate-mapping>


Code between sessionFactory.openSession() and session.close():

public virtual Result Get(string query, RefParam< CaseSetCollection > collection)
{
collection.Value = new CaseSetCollection();

try
{
this.OpenSession();
IList list = _session.CreateQuery(query).List();

foreach (object o in list)
{
CaseSet m = (CaseSet)o;
collection.Value.Add(m);
}
return new Result(true);
}
catch (Exception ex)
{
return new Result(false, ApplicationManager.StackExceptionMessages(ex), ex);
}
}

Full stack trace of any exception that occurs:
at NHibernate.Persister.Entity.AbstractEntityPersister.SetPropertyValues(Object obj, Object[] values) in C:\NewWork\NHibernate Source\src\NHibernate\Persister\Entity\AbstractEntityPersister.cs:line 232
at NHibernate.Impl.SessionImpl.InitializeEntity(Object obj) in C:\NewWork\NHibernate Source\src\NHibernate\Impl\SessionImpl.cs:line 2959
at NHibernate.Loader.Loader.InitializeEntitiesAndCollections(IList hydratedObjects, Object resultSetId, ISessionImplementor session) in C:\NewWork\NHibernate Source\src\NHibernate\Loader\Loader.cs:line 615
at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies) in C:\NewWork\NHibernate Source\src\NHibernate\Loader\Loader.cs:line 475
at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies) in C:\NewWork\NHibernate Source\src\NHibernate\Loader\Loader.cs:line 181
at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters) in C:\NewWork\NHibernate Source\src\NHibernate\Loader\Loader.cs:line 1798
at NHibernate.Loader.Loader.ListIgnoreQueryCache(ISessionImplementor session, QueryParameters queryParameters) in C:\NewWork\NHibernate Source\src\NHibernate\Loader\Loader.cs:line 1744
at NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet querySpaces, IType[] resultTypes) in C:\NewWork\NHibernate Source\src\NHibernate\Loader\Loader.cs:line 1738
at NHibernate.Hql.Classic.QueryTranslator.List(ISessionImplementor session, QueryParameters queryParameters) in C:\NewWork\NHibernate Source\src\NHibernate\Hql\Classic\QueryTranslator.cs:line 1124
at NHibernate.Impl.SessionImpl.Find(String query, QueryParameters parameters, IList results) in C:\NewWork\NHibernate Source\src\NHibernate\Impl\SessionImpl.cs:line 1770
at NHibernate.Impl.SessionImpl.Find(String query, QueryParameters parameters) in C:\NewWork\NHibernate Source\src\NHibernate\Impl\SessionImpl.cs:line 1728
at NHibernate.Impl.QueryImpl.List() in C:\NewWork\NHibernate Source\src\NHibernate\Impl\QueryImpl.cs:line 56
at ApplicationFramework.DAL.Bases.CaseSetDALBase.Get(String query, RefParam`1 collection) in C:\NewWork\ src\Components\ApplicationFramework\ApplicationFramework\DAL\Bases\CaseSetDALBase.cs:line 301


Name and version of the database you are using:
SQLServer 2005


Thank you very much for all your valuable time

Regards
Sudhagar.S