Edit page

Hello

I have a master table as Invoice that the primary key is InvoiceNO it is linked to invoicesdetails by the key

when i try to edit the Invoice I receive error saying:

<<< Record was NOT edited >>>
由于表 'invoicesdetails' 中了包含相关记录，不能删除或改变该记录。

this mean : because the invoicedtails contain a related record, this record can not be deleted or changed.

so what i am think to is to make the InvoiceNO readonly in edit page but in Add page it must not be readonly becos it is primary key

Please Help

waiting for your appreciated help