Complex query - help needed

[MaciejGolebiewski]

Hello,
I need to make some complicated query and desperately need help!

What I want to achieve is finding map sheets IDs using administrative units (let's say they would be NUTS as Polish names translate to English quite terribly).
I thought about 3 comboboxes (one for each NUTS level).
How it would work - when i choose by specified attribute (name) some NUTS1 in first combobox it should provide all NUTS2 units names that are within selected unit into 2nd combobox. Then when I select some NUTS2 unit of all provided before it should provide NUTS3 units names to 3rd combobox.
Nest to each combobox there should be also some tinny button which would trigger the actual query - listing all map sheets IDs from another service layer that intersect selected unit in a given combobox.
I think the attribute query sample (http://resources.arcgis.com/en/help/silverlight-api/samples/start.htm#AttributeQuery) is the thing to start.
Problem is how to feed next level queries with results from previous one - I thought of using the GraphicsLayer.
Second thing - how to achieve those trigger buttons feature.

Keep in mind that I'm quite a beginner so please be very understanding 😉

Cheers!
Thanks in advance for any feedback

[MaciejGolebiewski]

Any ideas anyone?

[MaciejGolebiewski]

Hi there,
I managed to run attribute query on NUTS1 level, now I need to perform identify task on the next level.
Is it even possible to use GraphicsLayer with results from previous query as a geometry on which identify task runs? There is Geometry property in IndentifyParameters Class, it accepts polygons, but I can't find how to use graphics layer instead of MapPoint.
Please help.