如何在Codeigniter中检查会话是否设置？

Question

我知道如何在核心PHP中创建会话,我已经了解如何在codeigniter中执行此操作,但我无法理解如何检查,如果会话已设置？我试图通过View检查这个,但它总是给我meesage Please Login.

请告诉我如何检查会话是否设置

调节器

if ($user_type=='Student')
{
  if ($LoginData=   $this->loginmodel->studentLogin($username,$password))
  {
    foreach($LoginData as $UserId)
    {
      $currentId= $UserId->StudentId;
    }
    //[[session]]

    $data['students_data']=         $this->loginmodel->student_profile($currentId);

    $this->session->userdata('$data');

    $this->load->view('students',$data);
  }
  else
  { 
  //$data['message']= array('Invalid Username or Password');
    $this->load->view('Login');
    echo "Invalid Username or Password";
  }
}
elseif ($user_type=="Faculty")
{
  if($data['faculty_data']=$this->loginmodel->faculty_admin($username, $password))
  {
    $this->session->userdata('$data');

    $this->load->view('faculty');
  }
  else
  {
    $this->load->view('Login');
    echo "Invalid Username or Password";
  }
}

视图

<?php 

if (!$this->session->userdata('$data'))
{
    echo "Please Login";
}
else
{

}

?>

<!DOCTYPE

Answer 1

创建会话:

$newdata = array(
               'username'  => 'johndoe',
               'email'     => 'johndoe@some-site.com',
               'logged_in' => TRUE
           );

$this->session->set_userdata($newdata);

要么

  $this->session->set_userdata('some_name', 'some_value');

但在此之前,请确保包含会话库.

$this->load->library('session');

获取会话数据:

if($this->session->userdata('whatever_session_name_is')){
     // do something when exist
}else{
    // do something when doesn't exist
}

Answer 2

 if ($this->session->userdata('variable') !== FALSE) {
  echo 'Variable is set';
} else {
  echo 'Variable is not set';
}  

更多信息

演示代码