To color alternate rows in a GridDataBoundGrid you would have to use the PrepareViewStyleInfo event.
private void gridDataBoundGrid1_PrepareViewStyleInfo(object sender, GridPrepareViewStyleInfoEventArgs e)
{
if(e.RowIndex > 0 && e.ColIndex > 0)
{
if(e.RowIndex % 2 == 1)
e.Style.BackColor = Color.LightBlue;
else
e.Style.BackColor = Color.DodgerBlue;
}
}