Updating text in listbox with radio button click

This seems like it should be pretty straightforward, but I am unsure where to put the code to make this happen.
I have a listbox with a bunch of file names. When I click one of 2 radio buttons I’d like the file names to change, and append some text to the end of the name.

What event handler would I attach this to?

action of the radiobutton.

http://documentation.xojo.com/api/deprecated/radiobutton.html#radiobutton-action

Then you could use http://documentation.xojo.com/api/deprecated/listbox.html#listbox-cellvalueat or simply rebuild the whole ListBox.

@Jean-Yves Pochez I tried that but it didn’t work.
@Gavin Smith ok, CellValueAt is a new one for me. I’ll give that a try.

Just to confirm, does ListBox.Refresh not do anything??

[quote=464876:@Gavin Smith]http://documentation.xojo.com/api/deprecated/radiobutton.html#radiobutton-action

Then you could use http://documentation.xojo.com/api/deprecated/listbox.html#listbox-cellvalueat or simply rebuild the whole ListBox.[/quote]
Ok so this appears to be in the new version. We are still on 2018 as we haven’t updated all of our apps yet…
How would I accomplish this in another way?

[quote=464888:@michael mellon]Ok so this appears to be in the new version. We are still on 2018 as we haven’t updated all of our apps yet…
How would I accomplish this in another way?[/quote]
https://documentation.xojo.com/api/deprecated/listbox.html.Cell

the action event of the radiobutton send a redraw to the listbox
the listbox redraws itself based on the radiobutton value.
or
the radiobutton action event redraws the listbox based on its value.