There is no way to add controls dynamically.
You can add all controls needed and hide them initially, showing them when you need them to be visible.
Production: NX10.0.3, VERICUT 8.0, FBM, MRL 3.1.4 | TcUA 10.1 MP7 Patch 0 (10.1.7.0) | TcVis 10.1
Development: VB.NET, Tcl/Tk Testing: NX11.0 EAP, NX12.0 EAP
How to Get the Most from Your Signature in the Community