> -----Original Message-----
> From: wxperl-users-admin@xxxxxxxxxxxxxxxxxxxxx
> [mailto:wxperl-users-admin@xxxxxxxxxxxxxxxxxxxxx]On Behalf Of Mattia
> Barbon
> Sent: December 6, 2003 1:06 PM
> To: Thomas Klausner; wxperl-users@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [wxperl-users] Grids and Data
>
>
> Il Tue, 2 Dec 2003 10:23:17 +0100 Thomas Klausner <domm@xxxxxx>
> ha scritto:
>
> Hello,
>
> > I'm currently developing a small application for in-house use.
> > Basically,
> > it's a database front end, i.e. users should be able to view,
> > insert, edit,
> > delete some data.
> >
> > I got some basic stuff working, but I'm wondering if there is a
> > "standard"
> > way of generating a Wx::Grid from database data.
> No, there isn't.
>
> > Here's what I'm doing:
> > in MyApp::new, I set up a panel, and generate a grid
> >
> > my $grid=Wx::Grid->new($panel,-1,wxDefaultPosition,[750,300]);
> >
> > I fetch stuff from a database (using Class::DBI):
> >
> > my @ks=ZCont::DB::Kostenstelle->retrieve_all;
> > my $rows=@ks || 1;
> > $grid->CreateGrid($rows,7);
> >
> > foreach my $kostenstelle (@ks) {
> > my $row=0;
> > my $col=0;
> > foreach(qw(kostenstelle titel beginn ende leitung overhead
> > budget)) {
> > $grid->SetCellValue($row,$col,$kostenstelle->$_);
> > $col++;
> > }
> > $row++;
> > }
> >
> > (If you're not familiar with Class::DBI : @ks is an array containing
> > objects. Each object as accessors which correlate to a column)
> >
> > This is working as expected, but there might be some better ways to
> > set up a
> > Grid ?
> Using a custom Wx::GridTable (there is a xample in the wxPerl demo)
> might be a good idea.
>
> > Additionally, some more questions (I'm coming from a Web
> > background..):
> >
> > Say I've got 1000 rows in a table, but only want to display 100 in
> > a Grid,
> > would I:
>
> > * fetch all 1000 columns and add/delete them from the Grid if the
> > user pages
> > up/down
> >
> > * fetch only 100, delete them when they disappear from the screen,
> > and fetch
> > new ones if they are needed (this is what I would do in a Web
> > Environment,
> > which is stateless)
> >
> > * something completly different?
> It depends. I think that, for a GUI application, it is better to display
> all 1000 rows at once and let the user scroll them using the scrollbars.
> If you use a custom Wx::GridTable you can fetch the rows on demand
> (thus avoiding fetching a large amount of data the user might not
> need/look at).
>
> HTH
> Mattia
>
> P.S.: I think that a generic "Database Grid" might be a good
> candidate for CPAN.
> if you feel like releasing it
>
I am also using Wx::Grid to display database data. Here is a snippet of code
I use to fill the grid using a statement handle. (The columns are
initialized elsewhere in the code)
my $max_col = $self->GetNumberCols() - 1;
my @row;
$sth->bind_columns( \( @row[ 0 .. $max_col ] ) );
my $row_count = 0;
my $col_count = 0;
while ( $sth->fetch() ) {
$self->AppendRows(1);
$self->SetCellValueXY( $row_count, $col_count++, $_ )
for (@row);
$row_count++;
$col_count = 0;
}
I was using Class::DBI methods to fill the grid much as Thomas was but I
found it too slow once the number of records gets higher. I am looking at
using Wx::GridTable but my performance is good enough right now (largest
grid is around 8 columns and close to a 1000 rows so not too big) so I have
not bothered.
My custom Wx::Grid class also allows the user to filter/sort any visible
column. If anyone is interested let me know and I will clean up the code,
comment it better, remove stuff specific to my application and post it.
Brad
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