ASPxCardView - How to implement a summary whose value depends upon an external editor value

The example below demonstrates how to calculate a summary in the CategoryID column based on the value in the ASPxSpinEdit residing below. Here is how the project works:

1) A custom callback is sent to the server within the editor's client side NumberChanged event handler.
2) Handle the SummaryDisplayText event to calculate the required summary value and set the e.Text parameter.