I'm trying to regenerate a Legend in a Pagelayout whenever the layers visibility are changed in the TocControl. What is the best way to catch when a layer visibility is changed?
Watch for the VisibilityChanged event on the feature layer that you want to track.
Something like the following (taken from here):
The links provided above point to ArcGIS 9.x content. If you plan on using ArcGIS 10, documentation is available here.