public void Xe_Insert(LoaiXe lx)
 {
     _db.table_Command("INSERT INTO Xe VALUES('" + lx.MaXe + "','" + lx.TenHangXe + "'," + lx.SoLuong + ",N'" + lx.ThongTinBaoHanh + "','" + lx.TenXe + "','" + lx.NhaSx + "'," + lx.DonGia + ",N'" + lx.TinhTrang + "')");
 }
 public void Xe_Update(LoaiXe lx)
 {
     _db.table_Command("UPDATE Xe SET TenHangXe = '" + lx.TenHangXe + "',SoLuong = " + lx.SoLuong + ",ThongTinBaoHanh = N'" + lx.ThongTinBaoHanh + "',TenXe = '" + lx.TenXe + "',NhaSX = '" + lx.NhaSx + "',DonGia = " + lx.DonGia + ",TinhTrang = N'" + lx.TinhTrang + "' WHERE MaXe='" + lx.MaXe + "'");
 }
 public void Xe_Delete(LoaiXe lx)
 {
     _db.table_Command("DELETE FROM Xe WHERE MaXe='" + lx.MaXe + "'");
 }