[GNUe] RE: gnue-forms grid implementation using wx.grid

[Johannes Vetter]

Hi Oleg,

We have thought about using wx.Grid for gnue-forms grid implementation
before we startet with it.  There were a few things we thought about.

The grid should support multi-line rows.  That means a record could be
made up from multiple "gridlines" which should be shown in the UI as a
single row. This should be reflected in the column-header as well.

The grid should not double the memory usage.  Since gnue-common might
keep all record data in memory (at least after a fetchall() is done)
using a wxGrid would double this requirement by having all that data in
the tables model too.  But the other way round could be a problem too.
If a db-driver (i.e appserver) does not keep all fetched records in
memory, the table model should still handle that.

The grid should be made up with the same tags in the xml-code and using
the same display/inputhandler [e.g. for autocompletion] as all other
entries do.  So the trick was to just use the same classes for this
purpose.  If we were using a wxGrid here, we had to write CellEditors
for all kind of GF* classes.  So if a dropdown changes its contents (for
example after entering/leaving filter mode) all CellEditors should
change their contents (while being in use already).  To stick with that
example: a wxChoiceCellEditor can change its parameters only via
SetParamters() which takes a comma separated string as argument.  That
would mean: no comma within a dropdown!  Of course, it might be possible
to derive own controls here.

It's been a long time ago we had to decide about this, so I might be
missing some important points here.  And maybe wxWidgets 2.8 has even
better support for wxGrid as it had in the past (2.6).

But one really good point is, we have a "nearly" working grid
implementation now, so there must be very good reasons to change the
concept of implementation now.

But maybe you could point us to some of that "good reasons" ... :)

Of course there are some sizer problems especially with grids atm, but I
think we could fix them as time goes by.  Or - I don't know wether
you're a wx-Expert or not - you might want to help us in improving the
wx-driver.

Anyway, your welcome and your help is really appreciated.


Thanks,
Johannes


-- 
BYTEWISE Software GmbH               Tel +43 (5577) 63377
i.A. Johannes Vetter                 Fax +43 (5577) 63381
A-6890 Lustenau, Enga 2              http://www.bytewise.at
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Individuelle Datenbanklösungen für GNU/Linux, Windows und
Mac OSX: http://www.bytewise.at/leistungen/gnue-indiv.html

signature.asc
Description: Dies ist ein digital signierter Nachrichtenteil