dgv.DataSource = myDateTable;

private static void SelectRowByOrderID(DataGridView dgv, string orderID)
    {
    dgv.Rows
             .OfType<DataGridViewRow>()
             .Where(x => (string)x.Cells["#"].Value == orderID)
             .ToArray<DataGridViewRow>()[0]
             .Selected = true;
    }