By Adam Nagy
You can use either the Inventor API to achieve this (from an AddIn, external application or VBA), but can also use iLogic.
If you have a Rule that is using directly the parameter you are interested in then that rule will be run when that parameter changes. If I have a model that has an extrusion with d0 height and d1 angle and create the below rules then they will be fired when those are changed:
s = d0 MsgBox("HeightChanged")
You can do the same with a Multi-Value parameter as well:
s = MultiValue MsgBox("MultiValue changed to " + s)
In case of using the Inventor API you can listen to the ModelingEvents.OnParameterChange event.