Dynamically populating live script dropdown control

I am trying the live script editor for the first time, and want to use the interactive controls. I see that I can add a dropdown menu, and manually edit it to supply a number of selections.

I would like, however, to dynamically populate the menu with selections. For example, my script might scan a directory looking for data files, and then I want to be able automatically have all those filenames loaded into the dropdown menu.

Is this possible?