Dynamically updating List Boxes based on selections

[#1]

I have a hierarchy based set of attributes which need to be displayed on my report as a set of list boxes. I need these boxes to only show me the relevant filtering in the next level filter. To simplify, say there is a Geography based hierarchy i have to work with. There are 3 levels in this hierarchy: Region, Country, City. I have to have 3 list boxes on my report, one each for Region, Country and City respectively. These List boxes should initially (prior to any selection) have all the possible values displayed. On selecting a single value in Region, there is a need to now only show the possible values of countries in the Country List Box and subsequently only the possible values of the cities in the City List box.(The normally grayed out selections should not be seen.)

Region	Country	City
APAC	India	Pune
APAC	India	Bangalore
APAC	India	Mumbai
APAC	China	Beijing
EU	France	Paris
EU	Germany	Berlin
EU	Germany	Hamburg

Eg: On selection of APAC in Region, only India and China should be visible in the Country List Box and Pune, Banagalore, Mumbai and Beijing

[swuehl · Accepted solution]

You can enable the option 'Hide Excluded' in general tab of list box properties and sort by State ascending.

Or create a list box field expression ('<Expression>' on field list drop down on general tab opens the expression editor), and enter

=aggr( YOURLISTBOXFIELD, YOURLISTBOXFIELD)

e.g.

=aggr( Country, Country)

or

=aggr(City, City)

[#3]

Fabulous! Thank you.