links in pagination in codeigniter - codeigniter

Question

in my view page,in the 1st form i have 2 select drop down...in the 1st drop down i am populating the value default from the controller...when u onchange the value in the 1st drop down,the selected value is passed to controller via javascript..in the controller,i get that 1st drop down value and load model and get value from model for the 2nd drop down and post it to view page...when u select the 2nd drop down value and click submit,the both drop down values are posted to controller after form validation and load model and get user information from the database and post it back again to view page ...this is the scenario for my view page..so,u can change the above both select drop down to get informations in the 2nd form in the same view page..now when i did pagination for my 2nd form user information,i am getting the links and data perfectly according to the limits and offsets..but,i am unable to retrieve the information when i click 2nd,3rd,4th..and rest on links while the informations are being posted from controller..so what can i do now?,,here is my code after i get both drop down values in the controller..
in my controller..
public function get_form_dept()
{
$this->load->helper(array('form', 'url'));
$this->load->library("pagination");
$this->load->library('form_validation');
$this->form_validation->set_rules('formation','Formation','required|required');
if($this->form_validation->run()== false) {
$this->viewstudent();
} else {
$config['base_url'] = base_url() . 'Incite/get_form_dept';
if($this->input->post('formation') == 1 && $this->input->post('department') == 1){
$config['total_rows'] = $this->db->get('user')->num_rows();
} else {
//$this->db->select('list_formation');
$query = $this->db->get_where('formation',array('id' => $this->input->post('formation')));
// echo $this->db->get_where('formation',array('id' => $this->input->post('formation')));
$row = $query->result();
foreach($row as $key) {
$get_formation = $key->list_formation;
echo $get_formation ."<br>";
}
$query1 = $this->db->get_where('department',array('id' => $this->input->post('department')));
$row1=$query1->result();
foreach($row1 as $key) {
$get_dept=$key->list_department;
echo $get_dept . "<br>";
}
//$array = array('formation' => $get_formation, 'department' => $get_dept);
//$config['total_rows']=$this->db->get('user',$array)->num_rows();
$query = $this->db->query("SELECT * FROM user where formation='$get_formation' and department='$get_dept'");
echo "SELECT * FROM user where formation='$get_formation' and department='$get_dept'" . "<br>";
$config['total_rows']=$query->num_rows();
//echo $row ."<br>";
//echo $row=$this->db->get('user',$array)->num_rows();
}
$config['per_page'] = 5;
//$config['uri_segment'] = 3;
//$choice = $config['total_rows'] / $config['per_page'];
// $config['num_links'] = round($choice);
$config['num_links'] = 2;
//$config['use_page_numbers'] = TRUE;
$config['suffix']= '?' . http_build_query($_GET, '', "&");
$this->pagination->initialize($config);
if($this->input->post('formation')== 1 && $this->input->post('department') == 1) {
// $this->db->limit($limit, $start);
$query_result = $this->db->get('user',$config['per_page'], $this->uri->segment(3));
$data['result']= $query_result->result();
} else {
$query = $this->db->get_where('formation',array('id' => $this->input->post('formation')));
$row = $query->result();
foreach($row as $key) {
$get_formation = $key->list_formation;
}
$this->db->where('id', $this->input->post('department'));
$query1 = $this->db->get('department');
$row1=$query1->result();
foreach($row1 as $key) {
$get_dept=$key->list_department;
//echo $get_dept;
}
$array = array('formation' => $get_formation, 'department' => $get_dept);
//$this->db->limit($limit, $start);
//$query = $this->db->get_where('user',$array);
$query_result=$this->db->get_where('user',$array,$config['per_page'], $this->uri->segment(3));
$data['result'] = $query_result->result();
}
$this->load->model('model_select_formation');
$data['formation'] = $this->model_select_formation->modelselectformation();
// query to fetch department
$data['dept']=$this->model_select_formation->get_department($data['formation_id']);
$data['formationid'] = $this->input->post('formation');
$data['departmentid'] = $this->input->post('department');
$this->load->view('viewstudent',$data);
}
}