If you are just getting information, you can also use the dynamic query adapter to run a BAQ and get the information that you want. The full adapters like PO are more useful when you are trying to manipulate data because they handle the whole dataset for you. But I don’t think you need the whole dataset for this case.
Check out the thread below for how to call a query in code. Basically, you’ll make a BAQ that runs on parameters to get the information that you want, then you can call that query in code, then you use the results to set the visibility of your control.