Hi,
I'm trying to get the value of a checkbox to send in an email form but I can't figure out the logic behind it. Can someone help please.

For the textfields I;m using (<p><strong>Name:</strong> {$data['Name']}</p> ) to display the data but the checkbox looks like it needs a value to be pre-populated beforehand i.e if I set the values to true it works, but it also ticks the checkbox by default.

The error i'm getting once I submit my form is; [Notice] Undefined index: error.

This is the code that I'm using;

public function Form() { 
        $fields = new FieldList( 
            new CheckboxField('Teacher'),
            new TextField('Name'), 
            new EmailField('Email'), 
            new TextareaField('Message')
            );        
        
        $actions = new FieldList( 
            new FormAction('submit', 'Submit') 
        ); 
    
         $validator = new RequiredFields('Email');
            return new Form($this, 'Form', $fields, $actions, $validator); 
    }
    public function submit($data, $form) { 
        $email = new Email(); 

        $email->setTo(''); 
        $email->setFrom($data['Email']); 
        $email->setSubject("Contact Message from {$data["Name"]}"); 

        $messageBody = " 
            <p><strong>Name:</strong> {$data['Name']}</p> 
            <p><strong>Email:</strong> {$data['Email']}</p> 
            <p><strong>Message:</strong> {$data['Message']}</p>            
            <p><strong>Teacher:</strong> {$data['Teacher']}</p>
        "; 
        $email->setBody($messageBody); 
        $email->send(); 
        return array(
            'Content' => '<h1>Thank you for getting in touch.</h1>',
            'Form' => '<h1>Thank you for getting in touch.</h1>'
        );
    }  

I couldn't get this working?

static $defaults = array (
    'MyBoolean' => '0'
);

The checkbox field will pass a '1' / 'true' if it's ticked - and nothing if it's not ticked.

Generally it's not too pretty to have the emails send "Teacher: 1".
Better to change it to a "yes" / "no"

$teacher = isset($data['Teacher'])  ? 'yes' : 'no';

        $messageBody = " 
            <p><strong>Name:</strong> {$data['Name']}</p> 
            <p><strong>Email:</strong> {$data['Email']}</p> 
            <p><strong>Message:</strong> {$data['Message']}</p>            
            <p><strong>Teacher:</strong> {$teacher}</p>
        ";