public List <ChiTietPhieuXuat> getPhieuXuatTheoThang(int startMonth, int startYear, int endMonth, int endYear)
{
DateTime startDate = new DateTime(startYear, startMonth, 1);
DateTime endDate = new DateTime(endYear, endMonth, 1);
endDate = endDate.AddMonths(1).AddDays(-1);
return(PhieuXuat.Where(p =>
p.PhieuXuat.NgayLap >= startDate &&
p.PhieuXuat.NgayLap <= endDate).ToList());
}
