closing/deleting a morph and dependents

>
> Hi Squeakers,
>
> i made a simple morph with submorphs. the submorphs are views for some domain
> objects and are dependents of them ( domainobj addDependent: mysubmorph ).
> Every thing works fine :-)
> but i can't figure out, how to remove my submorphs from the dependents list of
> my domain object, when I close/delete my morphic gui.
> It seems Morph delete does not call delete recursively on its submorphs. Is
> there an other way submorphs get informed when they are removed from the
> screen?
>
> Thanks in advance,
>
> Dietmar

> Hi Edgar,
>
> thanks for your answer :-)
> I will have to describe it better.
>
> Yes my morph and its submorphs disappear correctly when I close/delete it.
>
> My problem is, that the submorphs need to do some clean up (unregister as
> dependents from the domain objects)  when they disapear from the world . I
> tried to overwrite delete in my submorphs, but delete was not called on my
> submorphs when i closed/deleted my GUI.
>
> Here is a short sketch of my classes:
>
> I have a class Device (with attributes name, ip-Adress, port) which holds
> subdevices (objects of class Subdevice with attributes like name, description,
> state..)
>
> To view and edit Devices with their subdevices i made a DeviceMorph (for
> viewing/editing the "primitive" attributes of Device) and a SubdeviceMorph
> (for the SubDevices). Devicemorphs hold Subdevicemorphs as submorphs.
> Subdevicemorphs register themself as dependent on an Subdevice object so they
> get infomed when the  Subdevice changes it's state (just the squeak standard
> change notification mechanics). This works fine. I can open several
> DeviceMorphs for the same Device and a change on the device or its subdevices
> via one of the openDevice Morphs ist instantly displayed on all open
> DeviceMorphs for that device.
>
> When i close one of the DeviceMorphs observing my Device i need to unregister
> its SubDeviceMorphs from the SubDivices they have observed, because they are
> no longer visible and do not need the change notifications of their SubDevice
> anymore and because the reference from my SubDevice to my (now unvisible)
> SubDeviceMorph prevents the SubDeviceMorph from being garbage collected.
>
> Btw. I copied this design from the morphic counter example on
> http://wiki.squeak.org/squeak/795. The difference between the counter example
> an my problem is, that my domain objects live more independent of the GUI.
>
> I have seen that morphs can have a model, but i have no idea how to use it.
>
> Thanks again,
>
> Dietmar

>
> Thank for your links. I'll try to dig further into it.
>
> A first look into SwitchMorph raises a first question in me:
>
> When you call addDependent: should'nt be there a corresponding
> removeDependent: in the code?
>
> Maybe connection: should first call removeDependent: for the old connection
> before setting a new connection?
> Further, then I delete a SwitchMorph maybe  it should also disconnect from
> its's connections?