PrintDataGrid is correct. It must be added to stage in order to print
And I really hate that, not to mention other seriously limiting flaws with PrintDataGrid such as the ability to go back a page so it can be used for a print preview. Maybe we can get a decent version of PrintDataGrid that plays nice with print preview functions in Flex 4? If Adobe really wants Flex to gain popularity in the business environment, less crummy print support is really needed.
Current "print preview" options are lousy and don't scale to large print jobs well. I had to spend far too long creating a custom print preview dialog which works fine but I had to basically re-create my entire datagrid (and go to the appropriate page from the beginning) just to enable a "back" button in the preview! If you have a lot of pages it's slow...
Q1 - Probably the "best" examples I've seen on using PrintDataGrid have been Adobe's examples, which yeah, they don't allow so much flexibility.
I've yet to try 3.5's version but if it's anything like 2.0's..... bleh.