I have a one-to-many relationship where the child items for a parent are stored in an IDictonary. The mapping files are:





This loads my Survey object with an IDictionary of Survey Entries using:
private IDictionary surveyEntries = new Hashtable();
surveyEntries is private and I am writing class methods to access this dictionary.

I thought would be able to cast the IDictionary as a Hashtable e.g. the following code works:

IDictionary d = new Hashtable();
d.Add(1, 1);
d.Add(2, 2);
Hashtable h = d as Hashtable;
Console.WriteLine(h.ContainsKey(1).ToString());

When I execute the following I get an error:
Hashtable h = surveyEntries as Hashtable;
Any operation performed on h

The variable h is undefined after the cast and I get the exception:
An unhandled exception of type 'System.NullReferenceException' occurred in NHibernateTest.exe
Additional information: Object reference not set to an instance of an object.

I am using v1.0.2 running against an MSDE database.
Need help with Hibernate? Read this first:

NHibernate replaces your collections with its own implementations of their respective interfaces, so if your object was saved or loaded from the database, then the collection it has is actually not a Hashtable but NHibernate.Collection.Map.

Thanks for that. I want to write two methods to get an object from the collection, either by the key or index. Is this the most efficient way: