Andrew, this will work here, but not in my real-life application. In my application, I convert the selected value to a string that is calculated in a complex and performance demanding way (the code needs to iterate through views, etc....).

So, rather than perform these expensive calculations for each of the available values, I prefer to calculate only once: just for the value that was selected by the user. This works much faster (especially when the dropdown contains hundreds of values). 

 

Hence, the most straightforward approach to me is using a converter.

 

I could perform the calculations  in the "save" button of the document. But that's not an ideal solution here: I share the action buttons (save, submit, publish,...) accross many different document types, and the conversion needs to be done for only one particular type of document.