Tim
Have you tried TemplateGrid or ListView for this? Dataview contains, by definition, one object, so toggling through would not make sense. TemplateGrid, ListView and Datagrid have multiple objects, so toggling works. You could have a datagrid at the top of your page providing search capability for orders, and then have an order Dataview underneath that with a datasource of Listen To Widget pointing to your Order datagrid. Then when an Order is selected in the datagrid, you would see the details about that order in your listening dataview (including order items if you wish).
Mike