select box validation in Codeigniter

This will have the entry marked as "selected" as...selected by default. You want a multi-select dropdown, right?

<select name="schoolGroups[]" multiple="multiple"><option value="0" selected="selected">Select User Group</option><option value="1">Admin</option></select>

As for validation, you might want to build your own validation rule:

Your controller's method:

//...$this->form_validation->set_rules('schoolGroups','School groups','required|callback_check_default');$this->form_validation->set_message('check_default', 'You need to select something other than the default');//...

The add this other method:

function check_default($array){  foreach($array as $element)  {    if($element == '0')    {       return FALSE;    }  } return TRUE;}

If you just want a single select (no ability to multiselect then) it's even easier:

html:

<select name="schoolGroups"><option value="0" selected="selected">Select User Group</option><option value="1">Admin</option></select>

Method with validation:

 $this->form_validation->set_rules('schoolGroups','School groups','required|callback_check_default');  $this->form_validation->set_message('check_default', 'You need to select something other than the default');

Callback:

function check_default($post_string){  return $post_string == '0' ? FALSE : TRUE;}

The correct way of doing this is by setting the value of the default option to empty! Then you can use a simple form_validation rule like for a text field:

<select name="schoolGroups">  <option value="">Select User Group</option>  <option value="1">Admin</option></select>

.

$this->form_validation->set_rules('schoolGroups','School groups','required');

This one worked for me.

THE VIEW

<select name="schoolGroups[]" multiple="multiple">    <option value="">Select User Group</option>    <option value="1">Admin</option></select>

THE CONTROLLER

$this->form_validation->set_rules('schoolGroups','School groups','callback_check_default');

CALLBACK

function select_validate(){    $choice = $this->input->post("schoolGroups");    if(is_null($choice))    {        $choice = array();    }    $schoolGroups = implode(',', $choice);    if($schoolGroups != '') {        return true;    } else {        $this->form_validation->set_message('select_validate', 'You need to select a least one element');        return false;    }}