private void LoadCustomers()
        {
            CustomerBUS            bus       = new CustomerBUS();
            List <CustomerDisplay> list      = new List <CustomerDisplay>();
            List <CustomerDTO>     customers = bus.LoadAllCustomer();

            for (int i = 0; i < customers.Count(); i++)
            {
                list.Add(new CustomerDisplay()
                {
                    id = customers[i].ID, name = customers[i].Name, phone = customers[i].Phone
                });
            }
            listCustomer.ItemsSource = list;

            CollectionView view = (CollectionView)CollectionViewSource.GetDefaultView(listCustomer.ItemsSource);

            view.Filter = UserFilter;
        }