Hi,
   I don't know why after I put a single_hashtable in
another total_hashtable , the single_collection cannot be
retrieved if I set the single_hashtable  to nothing and
then create a new one with the same single_hashtable name
and add it to the total_hashtable. I can only retrieve the
last single_hashtable added to total_hashtable  from
reading total_hashtable. This means the following code
only works for the last added single_hashtable. It gave me
error message when I tried to retrieve the previous
hashtable. Please advise. Any suggestion will be
appreciated!

Dim tmyEnumerator As IDictionaryEnumerator =
total_hashtable.Item("Key").GetEnumerator()

error message:

An unhandled exception of
type 'System.NullReferenceException' occurred in
microsoft.visualbasic.dll

Additional information: Object variable or With block
variable not set.

Thanks,

wyy