How to submit the value of a disabled form field?

This page actually a preview where user can't change anything,that he has given before.I have tried bellow code,

echo $this->Form->input('exchange_type', array(
        'disabled' => 'disabled',
        'empty'   => '--Please Select--',
        'options' => array(
            '6' => 'POINT_TO_PRODUCT',
            '7' => 'POINT_TO_GIFT',
            '2' => 'POINT_TO_GAME'
        )
    ));

Here field has disabled but it's sending null value to database.I am trying to send actual value that user has been selected.How can I do this ?

Solution

That's how HTML works, values of disabled elements are not being sent.

What you can do is using a hidden field, that's what the form helper automatically does when using for example checkboxes, in order to ensure that there's always a value being sent, as unchecked checkboxes do not submit any value, just like disabled inputs.

The hidden field should have the same name as the actual field, and it should be placed before the actual field, that way the hidden value will only be sent in case the following element is disabled.

echo $this->Form->hidden('exchange_type');
echo $this->Form->input('exchange_type', array(
    'disabled' => true,
    // ...
));

That would pick up the previously POSTed value for both the hidden input and the select input, and the hidden input would be submittable.