private void dgvPartList_SortCompare(object sender, DataGridViewSortCompareEventArgs e)
    {
        if (e.Column.Name != "Group") return;
        e.SortResult = e.CellValue1.ToString().Length.CompareTo(e.CellValue2.ToString().Length);
        if (e.SortResult == 0) e.SortResult = e.CellValue1.ToString().CompareTo(e.CellValue2.ToString());
        if (e.SortResult == 0) e.SortResult = dgvPartList.Rows[e.RowIndex1].Cells["Description"].Value.ToString().CompareTo(dgvPartList.Rows[e.RowIndex2].Cells["Description"].Value.ToString());
        e.Handled = true;
    }