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; }