WinForms Data Grid - How to create an editable GridLookUpEdit with PopupContainerEdit

The WinForms GridLookUpEdit does not support editing in its drop-down grid. This example demonstrates how to implement a custom Grid-based Lookup that allows you to edit data within grid cells.

Follow the steps below:

Create a PopupContainerEdit.
Assign a panel to the PopupContainerEdit.Properties.PopupControl property.
Add the GridControl to the panel.
Handle PopupContainerEdit.QueryResultValue and PopupContainerEdit.QueryDisplayText events to synchronize the value and display text of the PopupContainerEdit with the state of controls displayed within the dropdown.