Conditional Constrained by Use

I have two entities Region and Location with a 1:* many relationship. On a Dataview I am trying to restrict the lookup of a Location to ones within the Region when a Region is selected or all locations if the Region is empty. I can do the first part using the "Constrained by" attribute of the Location field. However when the Region is empty I would like to be able to see all the Locations available. I seem to be able to do one condition or the other, Is there a simple way to achieve the desired conditional constraint or does anyone have an elegant way of achieving the same result?
1 answers

David, If I understand what you want to do, I think you could accomplish this by using a microflow to retrieve the selectable objects for your reference selector. You'll find this setting in the Selectable Objects section of the properties form. The microflow would be straightforward - check the Region, if it is empty, return all Locations, if it is populated, only return those that are for the selected region.

Hope this helps - Mike