Re: Passing Arguments in Revit Ribbon Elements

Both ComboBox and TextBox ribbon items have events. You'll want to use those events to see what their value is when they run your command.

1. ComboBox events:
   1. CurrentChanged
   2. DropDownClosed
   3. DropDownOpened
2. TextBox event:
   1.  EnterPressed 

Here is a resource with code examples for items you can build on a Ribbon: https://knowledge.autodesk.com/search-result/caas/CloudHelp/cloudhelp/2016/ENU/Revit-API/files/GUID-1547E521-59BD-4819-A989-F5A238B9F2B3-htm.html