private void DoiPhong_Load(object sender, EventArgs e)
 {
     LoadCBPhong();
     lblPhi.Text = "Phí đổi phòng: " + SQLConnection.SelectTS("TS_DoiPhongPhat");
 }
        private void btnAccept_Click(object sender, EventArgs e)
        {
            try
            {
                string   where1   = "IDPhong = N'" + soPhongCu + "'";
                DateTime checkIn  = Convert.ToDateTime(SQLConnection.SelectOne("NgayDen", "PhieuDatPhong", where1));
                DateTime checkOut = Convert.ToDateTime(SQLConnection.SelectOne("NgayDi", "PhieuDatPhong", where1));
                int      diffDays = SoNgayO(checkIn, checkOut);

                string where2       = "IDPhong = N'" + cbPhongMoi.SelectedValue.ToString() + "'";
                int    tongPhongMoi = diffDays * Convert.ToInt32(SQLConnection.SelectOne("GiaPhong", "Phong", where2));


                string _IDPhieuDatPhong = SQLConnection.SelectOne("IDPhieuDatPhong", "PhieuDatPhong", where1);
                string where3           = "IDPhieuDatPhong = " + _IDPhieuDatPhong;
                int    phatDoiPhong     = int.Parse(SQLConnection.SelectOne("PhiDoiPhong", "PhieuDatPhong", where1)) + int.Parse(SQLConnection.SelectTS("TS_DoiPhongPhat"));
                int    soLanDoiPhong    = int.Parse(SQLConnection.SelectOne("SoLanDoiPhong", "PhieuDatPhong", where1)) + 1;

                string val = "PhiDoiPhong = " + phatDoiPhong + ", SoLanDoiPhong = " + soLanDoiPhong +
                             ", IDPhong = N'" + cbPhongMoi.SelectedValue.ToString() + "'" +
                             ", TongCong = " + tongPhongMoi;
                SQLConnection.Update("PhieuDatPhong", val, where3);

                string valTrong   = "TinhTrang = 0";
                string valCoNguoi = "TinhTrang = 1";
                SQLConnection.Update("Phong", valTrong, where1);
                SQLConnection.Update("Phong", valCoNguoi, where2);
                MessageBox.Show("Thành Công!", "Đổi phòng", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Lỗi!", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        public DoiPhong(string soPhong)
        {
            InitializeComponent();
            lblPhong.Text = "Phòng cũ: " + soPhong;
            soPhongCu     = soPhong;
            string where1 = "IDPhong = N'" + soPhongCu + "'";

            if (int.Parse(SQLConnection.SelectOne("SoLanDoiPhong", "PhieuDatPhong", where1)) >= int.Parse(SQLConnection.SelectTS("TS_SoLanDoiPhong")))
            {
                MessageBox.Show("Vượt quá số lần đổi cho phép", "Lỗi", MessageBoxButtons.OK, MessageBoxIcon.Error);
                LockControl();
            }
        }