private void updateSales()
{
validateDates(calendarTerm.SelectionStart.Date, calendarTerm.SelectionEnd.Date);
lbl_Term.Text = $"Term: {calendarTerm.SelectionStart.Date.ToString("dd-MM-yyyy")} - {calendarTerm.SelectionEnd.Date.ToString("dd-MM-yyyy")}";
List <Order> allOrders = orderService.GetAllInRange(calendarTerm.SelectionStart, calendarTerm.SelectionEnd);
Dictionary <DateTime, List <Order> > ordersByDate = allOrders
.GroupBy(order => order.Date.Date)
.ToDictionary(kv => kv.Key, kv => kv.ToList());
lv_Sales.Items.Clear();
foreach (KeyValuePair <DateTime, List <Order> > pair in ordersByDate)
{
List <Order> orders = pair.Value;
List <int> customers = new List <int>();
int sold = 0;
int total = 0;
foreach (Order order in orders)
{
sold += order.Number;
total += order.Drink.Price * order.Number;
if (!customers.Contains(order.Student.Id))
{
customers.Add(order.Student.Id);
}
}
ListViewItem li = new ListViewItem(pair.Key.ToString("dd-MM-yyyy"));
li.SubItems.Add(sold.ToString());
li.SubItems.Add(total.ToString());
li.SubItems.Add(customers.Count.ToString());
lv_Sales.Items.Add(li);
}
}