[Gambas-user] TableView Problem

nando nando_f at ...951...
Wed Nov 2 17:57:23 CET 2005 

Thank you to the all who gave examples for TableView.

TableView is still implemented incorrectly.

TableView, *unlike* controls in VB (like Flexgrid), requires
a 2D array of some data (integer,string,etc) to 'refresh' the
TableView when it needs it. Hundreds of events fire wasting the CPU.
TableView is supposed to be like that in Flexgrid and others.
When data is placed in a cell, it is held static there until it is
changed.  It is not the responsibility of Program code to refresh it.
It is the responsibility of the control to do that.
Scrolling the Tableview (or clicking on it) isn't supposed to
require _Data event to fire because the data is already in cells.

Why does the data disappear when scrolled ?
It's not supposed to.
It doesn't make sense.
Even the QT control works 'statically'
TableView is implemented incorrectly.

If one is to have a TableView with data from many tables in MySQL,
this means that all scrolling and clicking REQUIRES the MySQL
queries be performed repeatedly because the cells are 'erased' every
scroll.  If it is a complex page with a lot of scrolling,
we are speaking of hundreds and thousands of queries.
Or, if, instead, a 'shadow' array is kept, then hundreds and thousands
of events are fired (_Data) just to repaint.

This is not correct.

But, perhaps, I am missing something.

Please inform me of my mis-understanding and mis-quidance.

-Fernando







---------- Original Message -----------
From: jose.santos at ...1197...
To: "gambas-user at lists.sourceforge.net" <gambas-user at lists.sourceforge.net>,
nando <nando_f at ...951...>
Sent: Wed,  2 Nov 2005 01:48:27 +0100
Subject: Re: [Gambas-user] TableView Problem

> Hi Nando. I'm not very sure about your problem.
> 
> I'm working in a database application and I've got TableViews that show
> perfectly more than 5.000 rows.
> 
> This is the code of the _Data event.
> 
> ' EVENTS.
> ' ================================================
> PUBLIC SUB Table_Data(Row AS Integer, Column AS Integer)
>   DIM objColumn AS DYGridColumn
> 
>   objColumn = m_columns[Column]
> 
>   SELECT CASE m_bytMode
>   CASE DYGridModesEnum.DYGridModeBound
>     m_rsData.MoveTo(Row)
>     m_table.Data.Text = m_rsData[objColumn.DataField]
>   CASE DYGridModesEnum.DYGridModeAddItem
>     m_table.Data.Text = Split(m_itemList[Row], m_strFieldSeparator)[Column]
>   END SELECT
> 
>   ' In Boolean Columns, An Icon is shown instead text values.
>   IF objColumn.DataType = DYDataTypes.DYBoolean THEN
>     IF CBool(CInt(m_table.Data.Text)) THEN
>       m_table.Data.Picture = UtilLib.IconOK()
>     ELSE
>       m_table.Data.Picture = UtilLib.IconCancel()
>     ENDIF
>     m_table.Data.Text = ""
>   ENDIF
> END
> 
> It can be a bit confussing but it's very simple:
> - FIRST SELECT: There are two working states: bounded to a database 
> or AddItem mode (an Array suplies the info to the TableView). -
>  Aditionally, For boolean values of the database, the TableView only 
> show icons instead of -1 or 0.
> 
> That's all. Hope you find it useful.
> 
> Regards.
> 
> Quoting nando <nando_f at ...951...>:
> 
> > Benoit,
> >
> > After much investigation, I have it appears that
> > TableView is not implemented correctly.
> > The example referred to originally (below) works, but
> > is not the correct way it is supposed to work.
> > The data in the table is 'deleted' every event '_data'
> > and an array is used to populate.
> > A control like this is supposed to hold data 'unchanged'
> > within the cells - even when scrolled or clicked.
> > 5000 events while scrolling to repopulate is unreal and is unnecessary.
> > The control/class is supposed to maintain the data - even when scrolling.
> > It is wrong.
> > The number of rows/columns at design time cannot be specified.
> > I cannot code something like...
> > TableView1[4,4].Text = "This is 4,4"
> > If TableView is the QT 'Table View' then it is incomplete
> >
> > Please help me understand this problem.
> > -Fernando
> >
> >
> > ---------- Original Message -----------
> > From: "nando" <nando_f at ...951...>
> > To: "Benoit" <gambas-user at lists.sourceforge.net>
> > Sent: Mon, 31 Oct 2005 17:49:31 -0500
> > Subject: [Gambas-user] TableView Question
> >
> >> I looked at the 'HOW TO PUT VALUES IN A TABLEVIEW WIDGET'
> >> located at 'www.gambasforge.net/code.php?id=31#notes'
> >>
> >> Can someone please inform me as to what makes
> >> SUB TableView1_Data  event fire?
> >>
> >> It is not evident to me.
> >>
> >> I single stepped through it - No code invokes it
> >> so it must be an event.
> >>
> >> -Fernando
> >>
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