Introduction

Quick Start

Basic Concepts

Understanding Routing

Intercepting Requests

Module Fundamentals

Database Operations

Templates

Helpers

Form Handling

Form Validation

Working With Files

Image Manipulation

Working With Dates & Times

Language Control

Security

Tips And Best Practices

Checkboxes and Radio Buttons

Checkboxes and radio buttons use a similar helper pattern as other form elements, with special handling for checked states.

Always do this:

In your view: Use value="1" for checkboxes
In your controller: Convert POST data to boolean for views, integer for database
In your database: Store as 0 or 1

Checkboxes

Use form_checkbox():

PHP

form_checkbox($name, $value = '1', $checked = false, $attributes = []);

Parameters

$name (string, required) - The name attribute for the checkbox
$value (string|bool|int, optional) - The value attribute. Defaults to '1'
$checked (mixed, optional) - Whether the checkbox should be checked. Defaults to false
$attributes (array, optional) - Additional HTML attributes. Defaults to []

Recommended Pattern (Best Practice)

For accessibility and improved usability, always wrap the checkbox input directly within the HTML <label> element. This allows users to click the text to toggle the checkbox, increasing the target area.

Note on Validity: Placing the input inside the label (implicit association) is perfectly valid HTML5 and the industry-standard best practice for these elements.

View File

<?php
echo '<label>'; // Start the label wrapper
echo form_checkbox('subscribe', 1, $subscribe_checked);
echo ' Newsletter Subscription'; // Place the text after the input
echo '</label>'; // Close the label wrapper
?>

The Checkbox Reality

Unchecked checkboxes don't submit any data. This is HTML behavior, not Trongate.

When a form submits:

Checked checkbox → POST contains subscribe='1'
Unchecked checkbox → POST contains no subscribe field

PHP

// After form submission:
$raw_value = post('subscribe', true); 
// If checked: returns '1'
// If unchecked: returns '' (empty string)

Here's something crucial: unchecked checkboxes don't submit anything.

If a checkbox is checked, the form submits its value. If unchecked, the field doesn't appear in the POST data at all.

PHP

// Checkbox was checked
post('subscribe', true); // Returns '1' (or whatever value you set)

// Checkbox was unchecked
post('subscribe', true); // Returns '' (empty string)

This is why you often see this pattern:

PHP

// In controller (submit method)
$data['subscribe'] = (int) (bool) post('subscribe', true);
// Converts to 1 if checked, 0 if unchecked

The Complete Pattern

Step 1: View File (Use Wrapping Pattern)

View File

<?php
echo '<label>';
echo form_checkbox('newsletter', 1, $newsletter_checked);
echo ' Newsletter Subscription';
echo '</label>';
?>

Important: The third parameter ($newsletter_checked) must be true or false.

Step 2: Controller (Two different conversions)

Your controller needs to handle data differently depending on whether it's going to the view or to the database.

PHP

class Members extends Trongate {
    
    // Display form (data goes TO view)
    public function create(): void {
        $update_id = segment(3, 'int');
        
        if ($update_id > 0 && REQUEST_TYPE === 'GET') {
            // Editing existing record
            $user = $this->db->get_where($update_id, 'users');
            $data['newsletter_checked'] = (bool) $user->newsletter;
        } else {
            // New form OR redisplay after validation error
            $data['newsletter_checked'] = (bool) post('newsletter', true);
        }
        
        $this->view('user_form', $data);
    }
    
    // Process submission (data goes TO database)
    public function submit(): void {
        $this->validation->set_rules('email', 'email address', 'required|valid_email');
        
        $result = $this->validation->run();

        if ($result === true) {
            $data['email'] = post('email', true);
            
            // Convert for database: 1 (checked) or 0 (unchecked)
            $data['newsletter'] = (int) (bool) post('newsletter', true);
            
            $update_id = segment(3, 'int');
            if ($update_id > 0) {
                $this->db->update($update_id, $data, 'users');
                set_flashdata('User updated');
            } else {
                $this->db->insert($data, 'users');
                set_flashdata('User created');
            }
            
            redirect('users/manage');
        } else {
            $this->create(); // Redisplay form with errors
            // Note: create() method fetches posted data for $newsletter_checked
        }
    }
}

Step 3: Database Schema

SQL

CREATE TABLE users (
    id INT PRIMARY KEY AUTO_INCREMENT,
    email VARCHAR(255),
    newsletter TINYINT(1) DEFAULT 0 -- 0 = no, 1 = yes
);

Two Different Conversions

When working with checkboxes the type of conversion that happens differs, depending on whether the goal is to render a view file or enter a checkbox value into a database.

Destination	Needs	Conversion	Result
View (form_checkbox)	Boolean	`(bool) post('field', true)`	`true` or `false`
Database	Integer 0/1	`(int) (bool) post('field', true)`	`1` or `0`

Common Pitfalls

Never use string values for checkboxes.

View File

// ❌ CONFUSING
echo form_checkbox('newsletter', 'yes');

PHP

// Then you need messy checks:
$value = post('newsletter', true); // 'yes' or ''
$is_checked = ($value === 'yes'); // Have to check string
$for_db = (int) ($value === 'yes'); // Even more complex

Do this: Always use 1 as the value

View File

// ✅ CLEAR
echo form_checkbox('newsletter', 1, $newsletter_checked);

PHP

// Simple conversions:
$for_view = (bool) post('newsletter', true);    // true/false
$for_db = (int) (bool) post('newsletter', true); // 1/0

Radio Buttons

Radio buttons are simpler - they always submit a value. You should also wrap the radio input within the <label> element for accessibility.

PHP

form_radio($name, $value = '', $checked = false, $attributes = []);

Parameters

$name (string, required) - The name attribute for the radio button
$value (string|bool|int, optional) - The value attribute. Defaults to ''
$checked (mixed, optional) - Whether the radio button should be checked. Defaults to false
$attributes (array, optional) - Additional HTML attributes. Defaults to []

Radio Group Example (Recommended Pattern)

View File

<?php
$status_options = [
    'active' => 'Active',
    'inactive' => 'Inactive', 
    'pending' => 'Pending'
];

foreach ($status_options as $value => $label) {
    $is_checked = ($current_status === $value);
    echo '<label>';
    echo form_radio('status', $value, $is_checked);
    echo ' ' . $label;
    echo '</label>';
}
?>

PHP

// Controller - both view and database use the same value
public function create(): void {
    $update_id = segment(3, 'int');
    
    if ($update_id > 0 && REQUEST_TYPE === 'GET') {
        $record = $this->db->get_where($update_id, 'items');
        $data['current_status'] = $record->status;
    } else {
        $data['current_status'] = post('status', true);
    }
    
    $this->view('form', $data);
}

public function submit(): void {
    // Same value works for both view and database
    $data['status'] = post('status', true);
    $this->db->insert($data, 'items');
}

Multiple Checkboxes

For multiple selections, store as JSON array:

View File

<?php
$categories = ['web', 'mobile', 'design', 'marketing'];
$selected_cats = $selected_categories ?? [];

foreach ($categories as $category) {
    $is_checked = in_array($category, $selected_cats, true);
    echo '<label>';
    echo form_checkbox('categories[]', $category, $is_checked);
    echo ' ' . ucfirst($category);
    echo '</label>';
}
?>

PHP

// Controller
public function submit(): void {
    $selected = post('categories', true) ?: []; // Array or empty array
    $data['categories'] = json_encode($selected);
    $this->db->insert($data, 'projects');
}

Quick Reference

Element	View Code	To View (boolean)	To Database
Checkbox	`<label>...form_checkbox('field', 1, $checked)...</label>`	`(bool) post('field', true)`	`(int) (bool) post('field', true)`
Radio	`<label>...form_radio('field', 'value', $checked)...</label>`	`post('field', true)`	`post('field', true)`
Text Input	`form_input('field', $value)`	`post('field', true)`	`post('field', true)`

Remember: Checkboxes are the only form element that needs different handling for views vs. databases. Everything else uses the same value for both.

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