We have a requirement to make a few project details available as standard AutoCAD fields (plain text fields, if that makes a difference), and have them re-evaluated on, for example, a regen. Although I'm aware of AcDbField and AcFdFieldEvaluator and have tried to create things correctly, I never see anything I recognise as mine in the Insert - Fields... dialog. The [ObjectARX] help files only detail the classes and don't give details of how the whole field system works, and the sample given with ObjectARX is very unhelpful - it creates a bunch of objects and doesn't really explain what's going on. If you load the resulting DBX from that compiled sample, although the registry entries get set as expected, nothing works - neither TEXTFILEFIELD nor TNF are recognised as commands and nothing appears in the Insert - Field... dialog.
Do I need evaluators and evaluator loaders? It seems a huge amount of overkill for a simple field. I don't understand why you don't just derive from AcDbField and have that override a virtual function the system can call to get the updated value.
Assuming I need all of this stuff - including registry entries - can anyone outline the steps I need to take to get my field listed under Insert - Field... and to call into my code to get an updated value on regen?