private void SaveButton_Click(object sender, RoutedEventArgs e) { IdTextBox.Text = ReturnedItem.GetNextReturnsId().ToString(); if (IsDataInCorrectForm()) { ReturnedItem.AddReturnedItem(CreateReturnedItemFromData()); if (_selectedCustomer == null) { return; } _selectedCustomer.ContactInfo = CustomerInfoTextBox.Text; Customer.UpdateCustomer(_selectedCustomer); MessageBox.Show("Successfully Added!!", "Information", MessageBoxButton.OK, MessageBoxImage.Information); NotifyObservers(); } else { MessageBox.Show("Incomplete Data!!", "Information", MessageBoxButton.OK, MessageBoxImage.Information); } }