How to set record in a form as read only based on custom logic using form personalization

Dear All,

I need to make the whole record in Invoice Entry form as read only based on some condtion so that if condition is true then no filed is updateable for this invoice.

I tried with forms personalization to set for Property 'Block' INV_SUM_FOLDER  UPDATE_ALLOWED to FALSE

but it makes all records in INV_SUM_FOLDER  not updateable.

Personalization is set on event WHEN-NEW-RECORD-INSTANCE INV_SUM_FOLDER.

Thank you in advance,

Alla.