**Course Title:** Mastering CodeIgniter Framework: Fast, Lightweight Web Development **Section Title:** Routing, Controllers, and Views in CodeIgniter **Topic:** Passing data between controllers and views --- ### Introduction In CodeIgniter, controllers are responsible for handling HTTP requests and providing data to views. Passing data between controllers and views is a crucial aspect of building dynamic web applications. In this topic, we will explore the different ways to pass data from controllers to views in CodeIgniter. ### Method 1: Using the View Data Function One of the simplest ways to pass data from a controller to a view is by using the `view_data()` function. This function allows you to pass variables to the view and render them as data. **Example:** ```php // controllers/Users.php public function index() { $data['title'] = 'User List'; $data['users'] = $this->user_model->get_users(); $this->load->view('users', $data); } // views/users.php <h1><?= $title?></h1> <ul> <?php foreach ($users as $user) :?> <li><?= $user->name?></li> <?php endforeach;?> </ul> ``` In the above example, we are passing two variables, `$title` and `$users`, from the controller to the view using the `view_data()` function. ### Method 2: Using the View Composer The view composer is a feature in CodeIgniter that allows you to inject data into the view at the time of rendering. You can use it to pass variables from controllers to views. **Example:** ```php // controllers/Users.php public function index() { $users = $this->user_model->get_users(); $this->load->view('users', ['users' => $users]); } // views/users.php <?= $users?> ``` In the above example, we are passing a variable `$users` from the controller to the view using the view composer. ### Method 3: Using the Flashdata The flashdata is a way to pass temporary data from one controller to another or to a view. It is stored in the session and can be used to pass data that needs to be accessed by multiple controllers or views. **Example:** ```php // controllers/Users.php public function create() { $this->session->set_flashdata('message', 'User created successfully!'); redirect('users/index'); } // views/users/index.php <?= $this->session->flashdata('message')?> ``` In the above example, we are passing a message from the controller to the view using the flashdata. ### Method 4: Using Query String You can also pass data from a controller to a view by using query string. This method is useful when you need to pass data that is not related to the controller's data. **Example:** ```php // controllers/Users.php public function index($id) { $user = $this->user_model->get_user($id); $this->load->view('users', ['user' => $user]); } // views/users.php <?= $user->name?> ``` In the above example, we are passing a user's name from the controller to the view using the query string. ### Best Practices * Always use the `view_data()` function to pass data from controllers to views. * Use the view composer to inject data into the view at the time of rendering. * Use the flashdata to pass temporary data from one controller to another or to a view. * Use query string to pass data that is not related to the controller's data. ### Additional Resources * [CodeIgniter Documentation](https://codeigniter.com/userguide3/workflow.html#view-data) * [CodeIgniter Documentation](https://codeigniter.com/userguide3/application_configuration/runtime.php#view-composer) * [CodeIgniter Documentation](https://codeigniter.com/userguide3/loader.html#flashdata) * [CodeIgniter Documentation](https://codeigniter.com/userguide3 advanced(input.html#query_string)) ### Leave a comment or ask for help! What is your favorite way to pass data from a controller to a view in CodeIgniter? Share your experience in the comments below!