[Pythoncard-users] Form validation "best practice" ?

[Fred P. <fr...@di...>]

Hi,

I have a very common task at hand here : from a PyCard 
'background' I display a custom dialog with a bunch of fields for the 
user to fill in. If the "form" is "submitted" (OK button) I need to 
validate some of the entered values and maybe ask additional 
questions (create this directory ?) and/or display messages (could 
not open this file), etc., and decide what to actually do afterwards.

My question is about how to do this elegantly both ways :

- in the interest of the user : staying in the 'context' of the form 
during the validation steps/messages, keeping the correct values 
while reverting incorrect ones to previous values/defaults, making 
sure only valid information is finally saved after whatever 
combination of Yes/No/Cancel responses, etc.

- in the interest of the code maintainer : can/should everything be 
centralized in the calling parent's code, or in the actual dialog's 
code ?  In the former case wouldn't there be potentially annoying 
'flicker' caused by the parent redisplaying the dialog ? In the latter 
case it seems I might need a way to not actually 'accept' a dialog 
although the 'OK' button was used, is this even possible ?

Any tips or examples of such handling in a pyCard context 
welcome... TIA,
fp