Multithreaded access to HTTPApplicationState

[Bob Reader]

I am new to multithreading concepts and want to ensure i am doing the
following correctly:

I am planning to create a custom object and store it in the
HTTPApplicationState of an ASP.Net application. This custom object will be
created at startup and not modified thereafter. The object will have one
property which holds a Hashtable. The Hashtable uses strings for keys and
ListDictionaries for values. Each ListDictionary uses strings for keys and
strings for values. The custom object will have a method that looks up and
returns strings stored in the ListDictionaries.

The .NET help file says "A Hashtable can safely support one writer and
multiple readers concurrently" without using a "Synchronized" wrapper or
using the syncroot. Is this also true of a ListDictionary? Can I call my
lookup method on the custom object without having to worry about
multithreading since the objects are never modified after they are created,
and only read thereafter? Do I need to synchronize read access to the
property on my custom object that holds the Hashtable?

Thank you for your help,
Bob Reader