public static int tinhThamNienTaiTruong(HRMDB0Entities db, NhanVien nv)
        {
            var tongThoiGian = new DateRanges();

            foreach (var ct in db.nvQTLamViec.Where(ct => ct.NV_id == nv.id))
            {
                tongThoiGian.Add(ct.ThoiGianBatDau, ct.ThoiGianKetThuc);
            }
            foreach (var lv in db.nvQTNghiNganHan.Where(lv => lv.CongTac.NV_id == nv.id))
            {
                tongThoiGian.Sub(lv.NgayBatDau, lv.NgayKetThuc);
            }
            return(tongThoiGian.ToMonths());
        }
        public static int tinhThamNienGiangDay(HRMDB0Entities db, NhanVien nv)
        {
            var tongThoiGian = new DateRanges();

            foreach (var ct in db.nvQTLamViec.Where(ct => ct.NV_id == nv.id)
                     .Where(ct => ct.ChucDanhChucVu_id.HasValue && ct.ChucDanhChuyenMon.laDayHoc))
            {
                /*if (ct.ChucDanhChuyenMon.tenChucDanhChuyenMon.ToLower().Contains("giảng")
                || ct.ChucDanhChuyenMon.tenChucDanhChuyenMon.ToLower().Contains("giáo"))*/
                tongThoiGian.Add(ct.ThoiGianBatDau, ct.ThoiGianKetThuc);
            }
            return(tongThoiGian.ToMonths() +
                   db.NhanViens.All.Find(nv.id).nvTTMoRongs.Single().ThamNienGiangDay_Truoc);
        }