//MENU
        private void AddNewClient_Click(object sender, RoutedEventArgs e)
        {
            AddClient ac = new AddClient();

            ac.Show();
            this.Hide();
        }
        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            AddClient ac = new AddClient();

            ac.Show();
            this.Hide();
        }
        private void Button_Click_2(object sender, RoutedEventArgs e) // Кнопка "Добавить клиента"
        {
            AddClient ac = new AddClient(conString);

            ac.Show();
        }