Dropdown box display a text but provides key value. How to achieve it on UNX DS?

Hi.

I am facing an issue trying to fix but it does seem a simple thinh to do in other languages (JS,...)

I am populating dropwdown box using a data source that has a initial view as this one

ColA     ColB

Sel1     1

Sel2     2

When defining the dropdown box using databinding propertu I am selecting the dimension associated to ColA. My aim is that dropdown box simply shows values such as Sel1, Sel2....

But once clicked I would like to know which is the value of the ColB associated to my selection (e.g: 1.2.....) to use it for other purposes (e.g: answer variable on a prompt query)

Does it exist a simple way to do it if data source is based on a UNX query (when text and keys are the same)?

Thanks