[Gambas-user] TableView Problem

[Eilert]

Hi Fernando,

you are right :-) I tried this

> To count the _DATA events, do (similar to) the following.
> 
> Create a label called Label_Count
> with TEXT as 0 (zero)
> 
> The first code line inside the _Data event for the TableView..
> Label_Count.Text = Label_Count.Text + 1
> 
> ... now scroll and/or click on your TableView.
> 
> Watch the count

and it turned out that even dragging another window over a TableView 
will trigger the _DATA event. So, yes, if in code you connect it 
directly to SQL queries, I guess you get into trouble. The only way to 
make it fast is to buffer the data in an array. Very strange.

However, on my machine this doesn't cause much CPU load. So, is this 
discussion somewhat academical? Benoit is not to blame for it, the 
Trolltech guys are. We cannot change this. So what?

> Also, notice how the Label is a static control.
> Its implementation is opposite to your comment.

Well - my comment was to never let graphical controls store any data for 
you, just display them. The only exception perhaps is with input 
controls like text boxes. You won't have another chance than accepting 
that they keep the original data for the time of user input (though you 
still could catch every keystroke and save it in parallel somewhere else).

During the last years I found that most data you want to display have to 
be processed before displaying, i. e. in case you let the displaying 
control save the data, you will have to re-process the data into the 
saving format afterwards because the user might have changed something 
(except when they're for display only, but this is a rare case here). 
This will make it necessary to write a lot of code reacting to clicks 
and processing/reprocessing data. So the program may become somewhat 
difficult to overview.

I found the advice from the guy (or guys) was good for me and my kind of 
projects. At that time, I had programmed one thing that displayed data 
processing them for display and displaying them in table view (this was 
VB then). After discussing some items with those folks, I began to code 
a new version of the software, and during the talks I got this advice. 
After trying to split my new program into distinct layers of storage, 
processing and display, I found it made it much clearer, so I'm 
following this rule ever since.

Rolf