Scope of a Grid or Grid Column Object
Both the grid and grid column objects can be instantiated from PeopleCode only.
A grid is a control on a page. You generally use these objects only in PeopleCode programs that are associated with an online process, not in an Application Engine program, a message subscription, a Component Interface, and so on.
In addition, PeopleSoft builds a page grid one row at a time. Because the Grid class applies to a complete grid, you can’t attach PeopleCode that uses the Grid class to events that occur before the grid is built; the earliest event you can use is the page Activate Event.