Using fields as variable in views
as arpitr says, you need to include the field so that it becomes visible to Views. You can exclude it from view in the field settings if you don't want it to show - then try, borrowed from (adjust appropriately for your setup) here:


  It's not super-obvious how to do this, but it is pretty easy.
  
  The downloaded filename has nothing to do with the "path" in the "data
  export settings" - that is simply the path that is used to trigger the
  generation of the file.
  
  To set the actual filename, click "settings" next to "CSV file" in the
  View's "format" section. Then, check the "provide as file" box and
  then set the filename (including token) there.