private void lvTables_MouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            Stoli s       = lvTables.SelectedItem as Stoli;
            int   idStola = Convert.ToInt32(s.idStola);

            if (MessageBox.Show("Освободить стол?", "Внимание", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
            {
                foreach (var item in db.Stoli)
                {
                    if (idStola == item.idStola && item.IsBusy == false)
                    {
                        item.IsBusy = true;
                        foreach (var i in db.Zakazi)
                        {
                            if (idStola == i.Stol)
                            {
                                i.DateCloseZakaz = DateTime.Now;
                            }
                        }
                    }
                }
                db.SaveChanges();
            }
            lvTables.ItemsSource = db.Stoli.ToArray().ToList();
        }
        private void btnOkay_Click(object sender, RoutedEventArgs e)
        {
            if (cbStoli.SelectedItem == null)
            {
                MessageBox.Show("Вы не выбрали стол!");
            }
            else
            {
                Stoli s = (Stoli)cbStoli.SelectedItem;

                if (s.IsBusy == false)
                {
                    MessageBox.Show("Стол занят!");
                }
                else
                {
                    foreach (var i in db.Stoli)
                    {
                        if (s.idStola == i.idStola)
                        {
                            i.IsBusy = false;
                        }
                    }
                    //new RegOrders(s.idStola,0,Login).ShowDialog();
                    this.Close();
                }
            }
        }