To make a field dynamically read only, use the CodeCharge Component Attributes feature. Here are the steps:

• Edit the form html and where the static text readonly will appear (assuming you want to this field to be always readonly) you will instead put this {RT_ID:readonly} Where RT_ID will be the name of the field as defined in code charge (Name attribute in field property)
• In the before show event of the field, include these lines

if ($RT_TABLE->EditMode)
{
	$Component->Attributes->SetValue('readonly', 'readonly');
}

Again where $RT_TABLE is the form name