“Concatenation”… That is a really long word, and full disclosure, I had to Google how to spell it.
The opening of the Revit API has done a great job of filling in gaps in Revit with some fantastic solutions. I am all for letting some features be done by third party developers; often they are closer to the problem and have a very unique approach to a solution that is clean and effective. Unfortunately, there are some fundamental things that Revit cannot do properly that an add-in only halfway solves.
Combining of different parameter values into a single parameter is one of those things that there have been some great solutions for with macros or Dynamo or add-ins, but they are all just stop gaps; they need to be run periodically to properly fill in that final parameter. They are not “automagic” and won’t keep an active eye on the parameters that they are combining.
It is past time for Revit to be able to do this natively and actively and consistently. I would imagine the easiest would be to have a calculated value, but that of course would not be ideal with the limitations around lack of tagging, etc. Some syntax for a shared or project parameter that allowed combining other parameters and they would stay up to date all the time, that would be the ideal solution.
This is a huge addition that I would love to see in a future release, and I am confident I am not alone. Until that time, unfortunately, we will have to keep rolling with band-aid solutions.