private void Button_Cancel_Click(object sender, RoutedEventArgs e)
        {
            var window = new VpsWindow();

            window.Show();
            Close();
        }
        private void Button_Add_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                _model.OperatingSystem = textOs.Text;
                _model.CPU             = textCpu.Text;
                _model.RAM             = textRam.Text;
                _model.Admin           = (Admin)cbAdmin.SelectedItem;
                _model.Owner           = (User)cbOwner.SelectedItem;

                _context.Get <VPS, IVpsRepository>().Persist(_model);

                _context.PersistState();
                var window = new VpsWindow();
                Close();
                window.Show();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }