I fired up autocad and turned on a bunch of events in MgdDbg and went through adding a label using dbconnect
Notice the new dictionary creation for 1CE and 1CF, these are in the NOD and called CONLDEFDictionary (1CE) which contains CablesLink1 (1CF) which has some xdata which holds the query
then later just before asking me for label location it creates dictionary 1D0 and 1D1, again these are in the NOD and called CONLABELDictionary (1D0) which contains CablesLabel1
The short story: doesn't seem to be a direct database event for catching this command.
I think if you implement an overrule on type ImpDBObject that you may be able to catch when these are used
Might be helpful to start out in your dictionary, and then knowing what dictionaries contain the label def you could catch the creation of the new MTEXT, which has xdata pointing to the label definition.
Customization file loaded successfully. Customization Group: ACAD
Customization file loaded successfully. Customization Group: CUSTOM
Customization file loaded successfully. Customization Group: MODELDOC
Customization file loaded successfully. Customization Group: CONTENTEXPLORER
Customization file loaded successfully. Customization Group: SKETCHUPIMPORTSKP
Customization file loaded successfully. Customization Group: EXPRESS
Regenerating model.
Loading MgdDbg...
AutoCAD menu utilities loaded.
Command: _RIBBON
Command: COMMANDLINE
Command: properties
Command:
Command:
Command: _MgdDbgEvents
Application Events Turned On ...
Database Events Turned On ...
Database Object Events Turned On ...
Dynamic Linker Events Turned On ...
Command: dbc
[App Event] : System Var Changing : DCTMAINdbc
[App Event] : System Var Changed : DCTMAINdbc
[App Event] : System Var Changing : DCTMAINdbc
[App Event] : System Var Changed : DCTMAINdbc
[App Event] : System Var Changing : DCTCUSTdbc
[App Event] : System Var Changed : DCTCUSTdbc
[App Event] : System Var Changing : DCTCUSTdbc
[App Event] : System Var Changed : DCTCUSTDBCONNECT
[Dynamic Linker Event] : Module Loading : c:\program files\autodesk\autocad 2014\condlg.arx
[Dynamic Linker Event] : Module Loading : ase.arx
[Dynamic Linker Event] : Module Loading : acmted2.arx
[Dynamic Linker Event] : Module Loading : acmted2.crx
[Dynamic Linker Event] : Module Loaded : ase.arx
[Dynamic Linker Event] : Module Loaded : acmted2.crx
[Dynamic Linker Event] : Module Loaded : acmted2.arx
[Dynamic Linker Event] : Module Loaded : c:\program files\autodesk\autocad 2014\condlg.arx
Command:
Command:
[DB Event : 728361680] : Database ConstructedDBC
DBCONNECT
Command:
[DB Event : 694855296] : Object Opened For Modify : <RegAppTable, 9>
[DB Event : 694855296] : Object Opened For Modify : <RegAppTableRecord, 1CD>
[DB Event : 694855296] : Object Appended : <RegAppTableRecord, 1CD>
[DB Event : 694855296] : Object Modified : <RegAppTableRecord, 1CD>
[DB Event : 694855296] : Object Opened For Modify : <DBDictionary, C>
[DB Event : 694855296] : Object Opened For Modify : <DBDictionary, 1CE>
[DB Event : 694855296] : Object Appended : <DBDictionary, 1CE>
[DB Event : 694855296] : Object Modified : <DBDictionary, 1CE>
[DB Event : 694855296] : Object Opened For Modify : <DBDictionary, 1CE>
[DB Event : 694855296] : Object Opened For Modify : <ImpDBObject, 1CF>
[DB Event : 694855296] : Object Appended : <ImpDBObject, 1CF>
[DB Event : 694855296] : Object Modified : <ImpDBObject, 1CF>
[DB Event : 694855296] : Object Modified : <DBDictionary, 1CE>
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUPREC
[App Event] : System Var Changing : AUPREC
[DB Event : 694855296] : System Var Changed : AUPREC
[App Event] : System Var Changed : AUPREC
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : System Var Will Change : AUNITS
[App Event] : System Var Changing : AUNITS
[DB Event : 694855296] : System Var Changed : AUNITS
[App Event] : System Var Changed : AUNITS
[DB Event : 694855296] : Object Opened For Modify : <DBDictionary, C>
[DB Event : 694855296] : Object Opened For Modify : <DBDictionary, 1D0>
[DB Event : 694855296] : Object Appended : <DBDictionary, 1D0>
[DB Event : 694855296] : Object Modified : <DBDictionary, 1D0>
[DB Event : 694855296] : Object Opened For Modify : <DBDictionary, 1D0>
[DB Event : 694855296] : Object Opened For Modify : <ImpDBObject, 1D1>
[DB Event : 694855296] : Object Appended : <ImpDBObject, 1D1>
[DB Event : 694855296] : Object Modified : <ImpDBObject, 1D1>
[DB Event : 694855296] : Object Modified : <DBDictionary, 1D0>Specify point for label:
[App Event] : System Var Changing : VIEWBACKSTATUS
[App Event] : System Var Changed : VIEWBACKSTATUS
[DB Event : 694855296] : Object Opened For Modify : <BlockTableRecord, 1F>
[DB Event : 694855296] : Object Opened For Modify : <MText, 1D2>
[DB Event : 694855296] : Object Appended : <MText, 1D2>
[DB Event : 694855296] : Object Modified : <MText, 1D2>
[DB Event : 694855296] : Object Modified : <BlockTableRecord, 1F>
[DB Event : 694855296] : Object Modified : <MText, 1D2>
[DB Event : 694855296] : Object Opened For Modify : <MText, 1D2>
[DB Event : 694855296] : Object Modified : <MText, 1D2>1 Record(s) linked with 1 Label(s)
Command:
[DB Event : 694855296] : Object Opened For Modify : <ImpSymbolTable, 1C9>
[DB Event : 694855296] : Object Appended : <ImpSymbolTableRecord, 1D3>
[DB Event : 694855296] : Object Modified : <ImpSymbolTableRecord, 1D3>
[DB Event : 694855296] : Object Opened For Modify : <ImpSymbolTableRecord, 1D3>
[DB Event : 694855296] : Object Modified : <ImpSymbolTableRecord, 1D3>