> On Sat, Aug 25, 2012 at 2:10 PM, Art Heimsoth > <artst...@artheimsoth.com> wrote: > >> I have the program working, but I really do not understand why. >> I had the following code at the start of the "Ok" method: >> >> resOK = self~OK:super >> resOK = 0 >> self~Finished = resOK\ >> > There are problems with that code. First off, never touch > finished. That attribute is for internal use only and should never > have been exposed to the users of the ooDialog framework. I know > that some of the example programs that came from IBM used it, which > was a completely wrong thing to do. > > Second, you should always call either the super class Ok() or super > class Cancel() methods to end your dialogs. That is the one way to > ensure that all the details of cleaning up the execution of the > dialog is done properly. > > And lastly, for what you want, you don't want the self~ok:super to > be at the start of the method, you probably want it as the very > last thing in your method. > >> I do want to do processing from that method, and do not >> necessarily want to end the program. >> > > Here is what you want to do, in semi-pseudo code: > > ::method ok unguarded > > -- First do your processing > do something > do some other things > > if <ok to close dialog> then do > -- Every thing is good, I want the > -- the dialog to close now. > return self~ok:super > end > else do > -- Some problem here, maybe the > -- user didn't fill in a required field, > -- I do *not* want the dialog to close > return 0 > end > >> I do not understand the purpose of the >> super operation - I have read the User Guide, but still do not >> really understand what it causes to happen. >> > > The purpose of it, in your case, is to close the dialog cleanly > with ok. Dialogs can only close with 2 states, ok or cancel. > Typically ok means 'whatever I was doing in the dialog, any changes > I made, etc. are good.' While cancel typically means 'whatever I > was doing in the dialog, any changes, etc., I don't want applied.' > > Technically what the clause "self~ok:super" means is: invoke the > ok() method in the super class of the 'self' object. > > An explanation of this is: the ooDialog framework implements a base > dialog class that does all the hard work of producing a Windows > dialog. When you use the ooDialog framework you are taking > advantage of all that hard work being done for you. You create / > program a subclass of the base dialog and just tweak a few things > to create a custom dialog. But, all the hard work is still done by > the base dialog. > > The base class has an ok() method where all the details (hard work) > of correctly ending the execution of the underlying Windows and > taking care of all the necessary clean up is done. If you do > nothing in your subclass, and the push button with a resource ID of > 1 (which is what IDOK equals) is pushed, the base class ok() method > executes, ends the dialog, and does all the clean up. > > On the other hand, if you want to tweak the way the dialog is > closed with the ok button, you add your own ok() method to your > subclass. The ok() method in your subclass is said to "over-ride" > the ok() method in the superclass. When the user presses the ok > button in the dialog, the ok() method in your subclass is invoked, > rather than the ok() method in the superclass. > > The whole subject of method over-riding is vast. But, we just want > to simplify this one thing to better understand it. So, in this > case we just say: > > You want to over-ride the ok() method so that you can do your own > processing. However, you still don't know what all needs to be > done to properly end the Windows dialog execution and you have no > idea what needs to be done to properly clean up. Therefore you > still depend on the superclass ok() method to end the dialog > properly. > > 1.) You over-ride the superclass ok() method to do your own > processing. > > 2.) You decide if you want the dialog to end, or not. > > 3a.) If you don't want the dialog to end, you just return from your > ok() over-ride. > > 3b.) If you do want the dialog to end, you invoke the superclass > ok() method to take care of the details for you. > Thanks, that was very helpful to me.
-- Art Heimsoth ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Oorexx-users mailing list Oorexx-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/oorexx-users
