PB : Catching delete & cut events / Returning nothing in some functions

[camille maurice <camille maurice thalesgroup com>]

Hello,

I'm currently designing objects for Dia, that can be linked and I'm 
wondering if its possible to catch events (like cut or delete) to avoid 
technical problems ?

I explain myself. I have a Box (first object) on which I can add 
Connector (second object). This second object should not exist whitout 
being on a Box. But when the user supress a Box its Conectors still exist.

I've seen in the sources that DiaObjects have parent/childrens 
attributes. Will it solve the problem if I used these instead of my own 
current lists ?

Another related problem, that I have, is I can't forbid the user to copy 
or cut the connector and paste it anywhere on the diagram (major problem 
for me if he does not paste it on a Box...). The "copy" problem : if I 
return NULL in the copy function of the Connector Dia crashes. The "cut 
event" one : I haven't find how to catch the event yet.

I've find some trick to delete unwanted copied Connectors (put a flag on 
them the they suppress themselves). But I still can't find any solution 
to catch these delete / cut events.

Thanks in advance,

Camille MAURICE
ATIM

Thales Services
Engineering & Process Management
Domaine de Corbeville
91404 ORSAY - FRANCE

PS : Please excuse my awful English