在codeigniter分页中使用orderby时出现问题

Question

我查看了从我的数据库中提取的几条记录。我实现了记录的分页，每页显示3条记录，并且工作正常。现在我希望提供一个下拉菜单，以便在记录的升序和降序之间切换。默认视图按升序排列。现在的问题是，当我从下拉列表中单击降序选项时，记录将更改为降序，但它会将我带到第一页。

当我更改记录的顺序时，我需要保持在同一页面上。有没有办法使用会话实现这一目标。因为我希望在不使用ajax的情况下解决这个问题。任何帮助，将不胜感激。谢谢。

这是我的控制器：

<?php 

class Datalist extends CI_Controller{
public function __Construct(){
parent::__Construct();
$this->load->model('myapp/list_model');
$this->load->helper(array('form','url'));
$this->load->library('session');
$this->load->library('pagination');
}

public function index(){

if(!isset($_SESSION["name"])){
 redirect("myapp/login");
}

$config['base_url'] = base_url()."index.php/myapp/datalist/index"."/";
$config['total_rows'] = $this->list_model->get_count();
$config['per_page'] = 3;
$config['uri_segment'] = 4;
$config['use_page_numbers'] = TRUE;
$config["num_links"] = 2;

$this->pagination->initialize($config);

if($this->input->post('order')){
 $_SESSION['order'] = $this->input->post('order');
}

if(isset($_SESSION['order'])){
 $order = $_SESSION['order'];
}else{
 $order = "ASC";
}

$limit = 3;

$offset = ($this->uri->segment(4))?$this->uri->segment(4):0;

$data['result'] = $this->list_model->get_list($offset,$limit,$order);

$data['games'] = $this->list_model->get_games();
$data['map'] = $this->list_model->get_map();

$data['links'] = $this->pagination->create_links();

$this->load->view('myapp/list_view,$data);

 }

}
 ?> 

这是我的模特

 class List_model extends CI_Model{

 public function __Construct(){
  $this->load->database();
}

public function get_list($offset, $limit, $order){

$offset = $offset-1;

if($offset<0){
  $offset = 0;
}

$from = $offset * $limit;

$query = $this->db->query("SELECT userData.Id,
                  userData.FirstName,
                  userData.LastName,
                  genderList.name,
                  userData.Email,
                  userData.Dob,
                  country.countryName,
                  state.stateName,
                  city.cityName,
                  userData.Pincode 
                  FROM userData 
                  LEFT JOIN country
                  ON userData.Country = country.countryId
                  LEFT JOIN state
                  ON userData.State = state.stateId 
                  LEFT JOIN city
                  ON userData.City = city.cityId
                  LEFT JOIN genderList
                  ON userData.Gender = genderList.genderId
                  ORDER BY userData.FirstName $order
                  LIMIT $limit OFFSET $from ");

return $query->result();
}

public function get_games(){
  $query = $this->db->query("select * from games");
  return $query->result_array();
}
public function get_map(){
  $query = $this->db->query("select * from mapGame");
  return $query->result_array();
}
public function get_count(){
  return $this->db->count_all("userData");
}
}
?> 

我的观点

<div class = "list">
  <table>
<thead>
  <tr>
    <th>FirstName</th>
    <th>LastName</th>
    <th>Gender</th>
    <th>Email</th>
    <th>DOB</th>
    <th>Interest</th>
    <th>Country</th>
    <th>State</th>
    <th>City</th>
    <th>Pincode</th>
  </tr>
</thead>

<tbody>
  <?php foreach($result as $data): ?> 
       <tr>
        <td><?php echo $data->FirstName; ?></td>
        <td><?php echo $data->LastName; ?></td>
        <td><?php echo $data->name; ?></td>
        <td><?php echo $data->Email; ?></td>
        <td><?php echo $data->Dob; ?></td>
        <td><?php 
          foreach($map as $mapping):
            if($data->Id == $mapping["userId"]){
              foreach($games as $name):
            if($mapping["GameId"] == $name["gameId"]){
              echo $name["name"]."<br>";
            }
              endforeach;
            }
          endforeach;
        ?>
        </td>
        <td><?php echo $data->countryName; ?></td>
        <td><?php echo $data->stateName; ?></td>
        <td><?php echo $data->cityName; ?></td>
        <td><?php echo $data->Pincode; ?></td></tr>
  <?php endforeach; ?>
</tbody>
</table>

<div align="center" style="margin-top:10px;background-color: #F1F8E0">
<?php echo $links; ?>
  </div>
</div>
<div class = "order">
  <?php 
  if(isset($_SESSION["order"])){
    if($_SESSION['order'] == 'ASC'){
     $order = 'ASC';
    }else{
     $order = 'DESC';
    }
  }else{
   $order = 'ASC';
  }
  echo form_open('myapp/datalist/index');
  echo form_label('Order');
  echo form_dropdown('order',array('ASC'=>'Ascending', 
   'DESC'=>'Descending'),$order,array('onclick'=>'this.form.submit()'));
  echo form_close();
  ?>
  </div>