how to update listbox list

[jgcramer]

I am fairly new to macros and vba so bare with me. I am working on a project and have a userform with a list of current models that the company provides, I want to make it as easy as possible to maintain so that when I leave they can still use the worksheet. I currently have the models in a worksheet and have the listbox row source listing the entire column where so that if they ever get new models they can just add to the column and it appears on the list, the problem is shows all the blank cells in the column as well so they can select them and it scrolls forever, is there a way for the row source to only include cells that have information in them included in the list.box? I wrote a quick example of what i am talking about and it's dumb but i couldn't provide the actually document because of the stuff from the company on it. listbox.xlsm
Thanks for the help.