Adding a form display method to a standard form

We can add display methods to tables and forms using extension classes. The table route is preferred, as tables are reusable. We sometimes need to add display methods to a form because some information is only available when the form is built, such as data on the form's data sources.

This is a limitation in that the display methods on forms cannot be added to the data source object, and they don't currently accept a record as a parameter. For this reason, they can only use the current record of a data source and cannot, therefore, be used as on-grid controls—they would show the same values on all rows.

In our case, we will write a display method to show information from a service order, in order to state that new orders will be attached to the service order. Of course, if this is intended as a warning, it needs...