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OpenACS has a form manager called ad_form. Ad_form has an adaptable UI. Error handling includes inline error reporting, and is customizable. However, ad_form can be tricky to use. In addition to this document, the ad_form api documentation is helpful.
Some elements have more than one choice, or can submit more than one value.
Creating the form element. Populate a list of lists with values for the option list.
set foo_options [db_list_of_lists foo_option_list "
select foo,
foo_id
from foos
"]
The variable foo_options should resemble {{first foo} 1234} {{second foo} 1235}
Within ad_form, set up the element to use this list:
{foo:text(select)
{label "Which Foo"}
{options $foo_options}
}This will result in a single name/value pair coming back in the submitted form. Handle this within the same ad_form structure, in the -new_data and -edit_data. In the example, it is available as $foo
See also the W3C spec for "The SELECT, OPTGROUP, and OPTION elements".
A situation you may run into often is where you want to pull in form items from a sub-category when the first category is selected. Ad_form makes this fairly easy to do. In the definition of your form element, include an html section
{pm_task_id:integer(select),optional
{label "Subject"}
{options {$task_options}}
{html {onChange "document.form_name.__refreshing_p.value='1';submit()"}}
{value $pm_task_id}
}
What this will do is set the value for pm_task_id and all the other form elements, and resubmit the form. If you then include a block that extends the form, you'll have the opportunity to add in subcategories:
if {[info exists pm_task_id] && $pm_task_id ne ""} {
db_1row get_task_values { }
ad_form -extend -name form_name -form { ... }
Note that you will get strange results when you try to set the values for the form. You'll need to set them explicitly in an -on_refresh section of your ad_form. In that section, you'll get the values from the database, and set the values as so:
db_1row get_task_values { }
template::element set_value form_name estimated_hours_work $estimated_hours_work
A good way to troubleshoot when you're using ad_form is to add the following code at the top of the .tcl page (thanks Jerry Asher):
ns_log notice it's my page!
set mypage [ns_getform]
if {$mypage eq ""} {
ns_log notice no form was submitted on my page
} else {
ns_log notice the following form was submitted on my page
ns_set print $mypage
}