MyClass1 has a 1-M unidirectional relationship with MyClass2. I want MyClass1 to have a Dictionary property (key=ID field of MyClass2, value=MyClass2). I tried using a map but can't get it to work. Can this be done?

Classes:
public class MyClass1
{
public int ID { ... }
public IDictionary<int, MyClass2> PMyClass2 {...}
}

public class MyClass2
{
public int ID { ... }
}

tables:
tblMyClass1: ID field (autoidentity)
tblMyClass2: ID field (autoidentity); FK_MyClass1ID (foreign key to tblMyClass1)

Mapping files - the <map> element is wrong but it's a placeholder for what I conceptually want :
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false">
<class name="MyClass1, DomainModel" table="dbo.tblMyClass1">
<map name="PMyClass2" cascade="all" outer-join="false">
<key column="FK_MyClass1ID"/>
<one-to-many class="MyClass2, Domain"/>
</map>
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false">
<class name="MyClass2, DomainModel" table="dbo.tblMyClass2" lazy="true">
<class>
</hibernate-mapping>

Thanks --
Bill

First of all, the <map> element requires an <index> element. Secondly, using an auto-generated ID as the index of a <map> poses a problem: you cannot add a MyClass2 to the map until you save it. In other words, what do you use as a key to add an unsaved MyClass2 to the map?

You may want to consider using a <set> or <bag> instead.

Thanks -- I reworked my class to use IList and have the dictionary generated from the modification of the IList. I use a <set> element for the list.