validate combo box in CodeIgniter - validation

Question

I am using CodeIgniter 3 where i am trying to validate my two combo boxes.
My code is like this:
view:
<tr>
<td >
<?php $extra=' class="selectCombo"';
$busVal=array();
$busVal[]="Select";
foreach($values as $val){
$busVal[$val->bus_id]=$val->bus_no;
}
echo form_dropdown('bus_id', $busVal,set_value('bus_id'),$extra);
?>
</td>
<td><?php echo form_error('bus_id');?></td>
</tr>
<tr>
<td >
<?php
$extra=' class="selectCombo"';
$route=array();
$route[]="Select";
foreach($values as $val){
$route[$val->route_id]=$val->route_name;
}
echo form_dropdown('route_id',$route,set_value('route_id'),$extra);
?>
</td>
<td><?php echo form_error('route_id');?></td>
</tr>
My controller code is like this:
public function add()
{
$this->form_validation->set_rules('bus_id', 'Bus', 'trim|required|callback_check_Bus');
$this->form_validation->set_rules('route_id', 'Route Name', 'trim|required|callback_validate_route');
if ($this->form_validation->run() == FALSE) {
echo 'Error';
}else{
}
}
public function check_Bus($val){
if($val ==0)
{
$this->form_validation->set_message('select_validate', 'Please Select Bus.');
return false;
}
else
{
return true;
}
}
public function validate_route($val){
if($val ==0)
{
$this->form_validation->set_message('select_validate', 'Please Select Route.');
return false;
}
else
{
return true;
}
}
I get following message for both fields:
Unable to access an error message corresponding to your field name Bus.(check_Bus)
Unable to access an error message corresponding to your field name
Route Name.(validate_route)
What should i do?

Answer 1

Use this code working fine.
callback validation rule
callback_fieldname_check
//function name callback_fieldname_check (){
}
// Set message - fieldname_check
see code
public function add()
{
$this->form_validation->set_rules('bus_id', 'Bus', 'trim|required|callback_bus_id_check');
$this->form_validation->set_rules('route_id', 'Route Name', 'trim|required|callback_route_id_check');
if ($this->form_validation->run() == FALSE) {
$this->load->view('load_your_view');
}else{
echo "Added";
}
}
public function bus_id_check($val){
if($val ==0)
{
$this->form_validation->set_message('bus_id_check', 'Please Select Bus.');
return false;
}
else
{
return true;
}
}
public function route_id_check($val){
if($val ==0)
{
$this->form_validation->set_message('route_id_check', 'Please Select Route.');
return false;
}
else
{
return true;
}
}