The question sounds obvious, nothing, but if your Datagrid has a fixed size, I think it's a bad idea to have a nice page with an empty space in the middle.
What are your favorite option? - Display a fake grey or pale dtagrid to simulate a disabled datagrid ? - Just a message to say that no data are present at the moment ? - Something else ?
The first choice seems for me the one to go, but the difficulty come when you don't know the column details.