Re: field navigation

Path: emory!swrinde!cs.utexas.edu!qt.cs.utexas.edu!yale.edu!spool.mu.edu!olivea!gossip.pyramid.com!pyramid!infmx!news From: cortesi@informix.com (David Cortesi) Newsgroups: comp.databases.informix Message-ID: <1992Jan23.182330.10835@informix.com> Date: 23 Jan 92 18:23:30 GMT References: <1605@das13.snide.com> Sender: news@informix.com (Usenet News) Reply-To: cortesi@informix.com Organization: Informix Software, Inc. paulb@p4.cs.man.ac.uk (Paul Bean) writes: > Is there a way to trap the direction in which the cursor is moving > through the fields on a form (ie forwards or backwards). I basically > want to ignore a next field x triggered by an after field y if i am > going backwards. greg@halexv.uucp (Gregory F. Hogg) offers: > I track direction in most all of my 4GL programs. Here is a code fragment > of how I do it: [clever code setting FieldNbr omitted] dave@das13.snide.com (Dave Snyder) writes: > In db4glgen I provide a way to check which key was hit to exit a field. > You can then act on those specific key sequences in your AFTER FIELD clauses. You should all begin to think about loosening your control over the cursor. Someday you may want to use these same forms under some kind of Graphical User Interface (GUI), where the user has total freedom of choice re what field to hit next. She/he clicks with the mouse on field 5, types, clicks on field 2, types, and so on, flitting like a butterfly over the form. Under these conditions, a program that assumes it has the kind of authoritarian cursor control you are discussing breaks very quickly. You should begin to adopt the outlook that the best form is one that puts NO constraints on the sequence in which fields are visited. This requires somewhat of a shake-up in the way you plan and design forms, but the conventions of GUIs, and the expectations of GUI-trained users, will ultimately force you to it. Hence, Paul: under a GUI window manager there IS no "backwards"; Greg: under a GUI, the fact that FieldNbr==3 would not imply that fields 1 and 2 have been visited, nor that field 4 has not; Dave: what keystroke do you expect to see, when AFTER FIELD f5 is invoked as a result of a mouse click in field f9 or f2? (PS. This has been a hypothetical discussion of visible industry trends in user interface design...)