private void TryCreateGround(object s, RoutedEventArgs e)
        {
            CoffeeViewModel x = (CoffeeViewModel)this.DataContext;

            x.GroundList.Add(new GroundModel()
            {
                Parent = x
            });
            x.NotifyChange("GroundList");
        }
        private void TryDeleteGround(object s, RoutedEventArgs e)
        {
            CoffeeViewModel x = (CoffeeViewModel)this.DataContext;

            if (x.GroundList.Count <= 1)
            {
                return;
            }

            int current_index = x.GroundList.IndexOf(x.CurrentGround);

            x.GroundList.Remove(x.CurrentGround);

            x.CurrentGround = x.GroundList[current_index - 1 < 0? 0 : current_index - 1];
        }
        private void Shutdown(object sender, CancelEventArgs e)
        {
            CoffeeViewModel x = (CoffeeViewModel)this.DataContext;

            Persistence.Save(x.GroundList);
        }