Selecting a potentially large number of rows in a DataGrid

Does anybody know if calling the Select method causes a paint to happen?
I'm assuming it does.

Under that assumption, if I have to select potentially a large number of
rows programatically how do I tell the datagrid not to repaint until the end?
It does not seem to have BeginUpdate/EndUpdate methods like some of the
other controls.

Thanks,

Oldman