How to use form Validation in Codeigniter?

  Use form Validation in Codeigniter

Paste in Codeigniter

if($this->input->post('login')){

$email=$this->input->post('login_email');

$password=$this->input->post('login_password');

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

$this->form_validation->set_rules('login_email', 'Email', 'required|valid_email'); 

                $this->form_validation->set_rules('login_password', 'Password', 'required|min_length[10]'); 

                if ($this->form_validation->run() == FALSE) { 

//redirect('dashboard');

//echo 'not-working';

            } 

            else { 

$query = $this->Customer_model->login_detail($email,$password);

if(count($query)>0){

//session_start();

$this->session->set_userdata('ID',$query[0]['ID']);

redirect('dashboard', 'refresh');

}

else{

redirect('register'); 

}  

} 

}