I have need to retrieve all of the items in a Datagrid from an external application using UIAutomation. Currently, I can only retrieve (and view in UISpy) the visible items.
I am 99% sure that this is not possible. UI Automation doesn't know about the data structures which are represented by the currently visible portion of a grid. It only sees what is visible. I think that you will have to page through the grid to get all the data (that is what I do).