Call to a member function login_model()

I'm new in CI. Can someone help me with this error?

//START OF ERROR

Code:

A PHP Error was encountered
Severity: Notice

Message: Undefined property: Main::$crud_model

Filename: controllers/main.php

Line Number: 297

Backtrace:

File: D:\Apache24\htdocs\framework\application\controllers\main.php
Line: 297
Function: _error_handler

File: D:\Apache24\htdocs\framework\index.php
Line: 315
Function: require_once

Fatal error: Call to a member function login_model() on a non-object in D:\Apache24\htdocs\framework\application\controllers\main.php on line 297
A PHP Error was encountered
Severity: Error

Message: Call to a member function login_model() on a non-object

Filename: controllers/main.php

Line Number: 297

Backtrace:

//CODE

PHP Code:

public function check_login(){

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

        $this->form_validation->set_rules('email', 'Email', 'required');

        $this->form_validation->set_rules('password', 'Password', 'required');

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

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

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

            $num_row = $this->crud_model->login_model($email, $password);

            //Validate Login / 0 = not valid / 1 = valid
                if($num_row->num_rows() > 0 ){

            //Statement of valid login
            //nag foreach ako then kinuha ko ay $user_id then nilagay ko sa variable na $my_id
                foreach($num_row->result() as $row):
                    $my_id['user_id'] = $row->user_id;
                endforeach;
            
                //Means: $_SESSION['user_id'] = $my_id
                    $this->session->set_userdata($my_id);

                //Means: $user_id = $_SESSION["user_id"];
                    $user_id = $this->session->userdata('user_id');
                
                //Function check_session in main.php
                    redirect(base_url() . 'main/check_session');

                }else{
                    redirect(base_url() . 'main/login' . '?email=' . md5(rand(1,1000)));
                
                }
                
                }else{
                    $this->login();
            }
         } 


//CODE for crud_model->login_model

PHP Code:

function login_model($email, $password){

        $this->db->where('email', $email);

        $this->db->where('password', $password);

        $query = $this->db->get('tusers');

        return $query;
    } 


@soljon,

I'm assuming that you are using CI3. Assuming that this is the case did you load the model crud_model into the class where the check_login function is located? Can we see the beginning of the class code where the check_login function is located?