Problem:

How to stop the form from submitting unless a correct value is added and compared with a custom field

Solution:

- Add a generic field in the form.

- Use the cred_form_validate hook to check against the entered field and the custom field in question:

https://toolset.com/documentation/programmer-reference/cred-api/#cred_form_validate

Add the custom code below according to the documentation:

<?php
add_filter('cred_form_validate','chr_validation',10,2);
function chr_validation($error_fields, $form_data)
{
    //field data are field values and errors
    list($fields,$errors)=$error_fields;
    //uncomment this if you want to print the field values
    //print_r($fields);
    //validate if specific form
    if ($form_data['id'] == FORMID)
    {
       
        //check my_field value
        if ($fields['generic-field']['value'] != types_render_field("custom-field", array()) )
        {
            //set error message for my_field
            $errors['generic-field'] = 'Please enter a correct PIN.';
        }
    }
    //return result
    return array($fields,$errors);
}

Replace FORMID with the ID of your form.

Replace custom-field with the slug of the custom field that you want to check against.

Replace generic-field with the slug of the generic field option you added in the form.

Relevant Documentation:

https://toolset.com/documentation/programmer-reference/adding-custom-code/using-toolset-to-add-custom-code/

Problem:
Update custom field value with the current timestamp programmatically.

Solution:
You can use the Toolset form's hook "cred_save_data" in order to update the custom field value on fly or programmatically.

You can find the proposed solution in this case with the following reply:
- https://toolset.com/forums/topic/saving-the-datestamp-of-when-an-update-is-done/#post-2365803

Relevant Documentation:
- https://toolset.com/documentation/programmer-reference/cred-api/#cred_save_data