Something to try.
Subscribe to the dv.ListChanged event where dv is your DataView.
dv.ListChanged += new ListChangedEventHandler(dv_ListChanged);
Then in the event handler, look for the Reset action. You may need to set a flag before you sort using dv.Sort as the reset action can occur for reasons other than a sort.
private void dv_ListChanged(object sender, ListChangedEventArgs e)
{
if(e.ListChangedType == ListChangedType.Reset)
{
//sorted
}
}