[prog] Filling an option list (was: perl woes...)

Mon Jun 2 16:31:33 EST 2003

Hello again!

> If you should ever find that way, Wolfgang, please share! (so would I,
> except I'm not really searching any more...)

Well, actually I have just done it quick-and-dirty for a test. I have to
say, you got me interested therein. Let me just re-phrase it a bit into
some kind of pseudo code for better understanding.

Of course I know these files are only little readable and maintainable; of
course there would be a lot of error detecting and error processing to do.
I just wanted to see how it works... as I just stated, quick and dirty.

I hope you can see the interesting part:
	- retrieve your data from the data base
	- see how you can stuff that data into the list of hash references
	  that HTML::Template->param() expects for the TMPL_LOOP tag(s)

Wolfgang

-- template file: optiontest.html.t --
<html>
<head>
<title>option test</title>
</head>

<body>
<h1>Option test</h1>

<form action="<TMPL_VAR ESCAPE=1 NAME="selfurl">" name="form1">
<select name="sel1" <TMPL_VAR NAME="sel1_disabled"> onChange="document.form1.submit();">
	<TMPL_LOOP NAME="sel1option">
	<option
		value="<TMPL_VAR ESCAPE=1 NAME="value">"
		<TMPL_VAR NAME="selected">
	>
		<TMPL_VAR NAME="text">
	</option>
	</TMPL_LOOP>
</select>
<input type="hidden" name="stage" value="1">
</form>

<TMPL_IF NAME="stage1">
	<hr>
	<p>Selection 1: <TMPL_VAR NAME="sel1selection">
</TMPL_IF>

</body>
</html>
--------------------------------------

-- script file: optiontest -----------
#!/usr/local/bin/perl -T

use strict;
use warnings;
use CGI;
use HTML::Template;

# Here I have some methods that do the actual data base processing.
# As an example,
#	getSomeQueryList()
# which returns a list of hash references, and the keys are the column
# names, say 'id' and 'name'.
#
use MyDataBaseInterfaceModule;

my $cgi = CGI->new();
my $page = HTML::Template->new(filename => "optiontest.html.t");
my $db = MyDataBaseInterfaceModule->new();

# a kind of a main loop:
#
if ($cgi->param("stage") == 1) {
	#
	# Form 'form1' has been submitted. The user has made the first
	# choice.
	#
	# Set all the template vars so that the page renders as wanted.
	#
	$page->param(stage1 => "true");
	$page->param(sel1selection => $cgi->param("sel1"));

	#
	# Entries for the option list.
	# Because I want to disable the drop-down list now, I don't have
	# to put in all the values; of course you can if you like to --
	# it will be similar to the 'else'-part. In this case you can
	# check each $item (see 'else'-part) for equality with
	# $cgi->param("sel1") -- the user's choice -- and set 'selected'
	# to "" or "selected".
	#
	my $selection = $cgi->param("sel1");
	$page->param(sel1option => {
		value => "",
		text => $selection,
		selected => "selected"
	});
	$page->param(sel1_disabled => "disabled");
} else {
	#
	# The form has not yet been submitted. So, get the appropriate
	# values and display them in the option list.
	#
	$page->param(stage1 => "");
	$page->param(sel1_disabled => "");

	my @anything = $db->getSomeTableList();

	#
	# construct that list of hash references that $page->param()
	# expects for that TMPL_LOOP tag. First, add a default entry
	# and then add the result of the data base request.
	#
	my @list = ();

	push @list, {
		value => "",
		text => "--please choose--",
		selected => "selected",
	};

	foreach my $item (@list) {
		my $id = $item->{'id'};
		my $name = $item->{'name'};

		push @list, {
			value => $id,
			text => $name,
			selected => "",
		};
	}

	$page->param("sel1option" => \@list);
}

print $page->output();
__END__
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