Maintenance view event for validation when changing data
I have a maintenance view on a table that should validate some fields during user input.
I am using event 05 'Creating a new entry' to validate fields when user creates new entry in the table. That works fine.
I would like to have the same validations happening when the user changes fields of records already existing in the database. I tried to use event 01 'Before saving the data in the database' but the problem with this is that user can change many fields of many records before clicking 'Save'. I would like to have the error raised for incorrect entry already after the change.
So far I could not find an event to do this but only by changing the code itself. The problem with that is whenever the code is regenerated the custom part is lost.
Is there an event I can use that would help me achieve this?
Thanks in advance.