Good day,

I working on controller, which pass parameter via URL to a custom object detail page's fields.

for instance :

Controller :

String accountMember = 'user1';

String accountMember2 = 'user2';

String URL = /a03/e?xxx111=accountMember&xxx222=accountMember2;

Custom object:

xxx111 is field id of accountMember and belong to text field type

xxx222 is field id of accountMember2 and belong to text field type

Problem :

accountMember fields are both read-only suppose, i do not see my parameter populate in fields until i make the field to visible on FLS

question :

1. why the readonly field can't get the parameter ?

2. if i make the fields to visible now, how can i make the fields not editable ? i try using validaton rule with formula 

isChange(accountMember__c) , it doesn't prevent user to edit before it get save, the validation only check after the record saved, any hint on this ?

Thanks!