# Back to the problem

:::{activity} Inventory system
:label: inventory-system-code

Complete the implementation of the problem in section {ref}`inventory-system`. Include in your project a class diagram and a screencast shorter than 10 s in your repository.

Use what we have learned:
- OOP
- `DataGrid` control for queued and processed orders
- The GUI will only observe queued and processed orders. Use `ObservableCollection<Order>` instead of `List<Order>` to automatically track the changes in the GUI.
:::