Tapestry updating grid with AJAX

Tapestry updating grid with AJAX

I'm trying to make the following work in Tapestry.
I have a Dictionary<String, Dictionary<String, Object>> which contains my
data.
I'm trying to accomplish that I have 1 drop-down menu (Select component)
which contains the keys from outer Dictionary.
When that selection changes, grid should be updated with the keys and
values from the selected sub-dictionary.
For example:
Dictionary<String, Dictionary<String, Object>> dictionaries = new
Hashtable<String, Dictionary<String, Object>>();
Dictionary<String, Object> dict1 = new Hashtable<String, Object>();
Dictionary<String, Object> dict2 = new Hashtable<String, Object>();
dict1.put("k1", "d1v1");
dict1.put("k2", "d1v2");
dict2.put("k1", "d2v1");
dict2.put("k2", "d2v2");
dictionaries.put("d1", dict1);
dictionaries.put("d2", dict2);
Would anyone would be so kind to give me an example or push me in the
right direction?