# To subscribers of the xforms list from Clive A Stubbings <xforms@vjet.demon.co.uk> :
>
> # To subscribers of the xforms list from Ivan Powis <Ivan.Powis@nottingham.ac.uk> :
>
> > I'm not sure I understand the problem. If the input is unterminated
> > (with a Return or Tab) then why should a callback be invoked?
>
> Because from a user's perspective the input field shows data which has
> been input but which the application is not aware of without being
> advised by the call back? As others have said this behaviour that a
> visible input is not actually valid is not intuitive.
>
Let me add to that ;-)
I have an applications with about a dozen input objects on a tab. It also
has a pile of buttons.
Pressing a button can change which data set is displayed (its a form of tree
navigation) so its vital to collect any changes.
If I do a "call all callbacks" on all input objects when any button is
pressed I would also have to compare the input data to find out if it had
changed since I also need this info.
More fun still, the form is on a tab folder, and there is some data duplication
between the tabs (ie some tabs provide a more detailed view of some of the
information). There are also other windows that also may contain some of
the data in text or graphical form.
Trying to find all the places that I would have to call the callbacks and then
work out which ones contained the "latest" "new" information would be
somewhat non-trivial. The net effect is that it makes the GUI code a lot less
modular.
I think the root of the "problem" is that xforms treats input objects as
having a special class of focus. ie clicking on a button should de-focus
an input object and do exactly the same processing as is done when
another input object is selected. I've not found a way to generate this
behavior from the "outside".. The key data is burried and invisible in
xforms.
Oh yes.. and of course just to confuse things, TAB doesn't work on multi-line
objects either.. but thats an old chestnut ;-)
Cheers
Clive
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