Drupal 7 - Submit function not triggered on theme table - drupal

Question

I want to be able to select items from two select lists and then submit (which will take me to another form.
The following is the code I have however the submit function (submit_function) does not appear to get triggered (it just refreshes the form). What am I doing wrong?
function myfunction($form, &$form_state)
{
$output = drupal_render($element['form_id']);
$output .= drupal_render($element['form_build_id']);
$output .= drupal_render($element['form_token']);
$header = array(
'columnone' => t('Column 1'),
'columntwo' => t('Column 2'),
'columnthree' => t('Column 3'),
);
$rows = array(
array(
'columnone' => array(
'data' => array(
'#type' => 'select',
'#options' => columnoneoptions(),
),
),
'columntwo' => array(
'data' => array(
'#type' => 'select',
'#options' => columntwooptions(),
),
),
'columnthree' =>array(
'data' => array(
'#type' => 'submit',
'#value' => t('Add'),
'#weight' => 45,
'#submit' => array('submit_function'),
)
),
),
);
$output['table'] = array(
'#theme' => 'table',
'#header' => $header,
'#rows' => $rows,
'#weight' => 2,
);
return $output;
}

Answer 1

That is quite normal, you are mixing form elements with static renderable elements. A drupal_get_form function expects a form build.
What you need to create is your custom form theme table which outputs a theme within a form build. Here is some sample code that could help you further:
function YOURMODULE_theme()
{
// define a table form theme
return array(
'YOURMODULE_table_form' => array(
'render element' => 'element'
),
);
}
function theme_YOURMODULE_table_form($vars)
{
$element = $vars['element'];
$form_keys = false;
$rows = array();
// loop through each row form elements
foreach (element_children($element) as $key) {
if (!$form_keys) {
$form_keys = array();
// retrieve the form keys for each row
foreach (element_children($element[$key]) as $f_key) {
$form_keys[$f_key] = isset($element[$key][$f_key]['#title'])
? $element[$key][$f_key]['#title']
: '';
}
}
$row = array();
foreach ($form_keys as $fieldkey => $fieldname) {
// render each field in a separate row
$row[] = array(
'data' => drupal_render($element[$key][$fieldkey])
);
}
$rows[] = $row;
}
// return a build for the table
return theme('table', array(
'header' => $vars['element']['#header'],
'rows' => $rows,
'empty' => isset($vars['element']['#empty'])
? $vars['element']['#header']
: '',
));
}
And the form using your logic:
function myfunction($form, &$form_state)
{
$form['table'] = array(
'#theme' => 'YOURMODULE_table_form',
'#header' => array(
'columnone' => t('Column 1'),
'columntwo' => t('Column 2'),
'columnthree' => t('Column 3'),
),
'#tree' => true,
);
$form['table'][0] = array(
'columnone' => array(
'#type' => 'select',
'#options' => columnoneoptions(),
),
'columntwo' => array(
'#type' => 'select',
'#options' => columntwooptions(),
),
'columnthree' => array(
'#type' => 'submit',
'#value' => t('Add'),
'#weight' => 45,
'#submit' => array('submit_function'),
),
);
return $form;
}