private void btn_XacNhan_Click(object sender, EventArgs e)
        {
            DB_QliKSDataContext db = new DB_QliKSDataContext();
            KhachHang           k  = new KhachHang();

            k.Ten      = txtb_TenKhachHang.Text;
            k.SDT      = txtb_SDT.Text;
            k.NgaySinh = dtpk_ngaysinh.Value;
            k.IDPhong  = cbb_PhongDat.Text;
            k.CMND     = txtb_CMND.Text;
            Phong p = db.Phongs.Where(o => o.ID == k.IDPhong).Select(o => o).FirstOrDefault();

            p.TrangThai = "Đặt Trước";
            db.KhachHangs.InsertOnSubmit(k);
            db.SubmitChanges();
            MessageBox.Show("Đặ Phòng Thành Công!");
        }
 private void detach_Phongs(Phong entity)
 {
     this.SendPropertyChanging();
     entity.LoaiPhong = null;
 }
 private void attach_Phongs(Phong entity)
 {
     this.SendPropertyChanging();
     entity.LoaiPhong = this;
 }
 partial void DeletePhong(Phong instance);
 partial void UpdatePhong(Phong instance);
 partial void InsertPhong(Phong instance);