User Interface (UI) Messages are the best way to pass data from a TestStand sequence to a User Interface.
UI messages are preferred for two reasons:
- Independence of UI and Sequence Files - A user interface should always run with any sequence file, and vice versa. By using UI messages, there is no requirement that certain properties exist in sequence files when using them with the user interface. With UI messages:
- the user interface can execute sequences that do not implement certain messages (the handling code in the User Interface simply never executes)
- Sequences that post custom messages can be executed in a UI that is not built to handle them (the UI message is just ignored by the User Interface)
- Maintainability - UI messages avoid dependence on Sequence File Properties or UI variables, meaning less to maintain for developers of both sequence files and user interfaces
A detailed tutorial for implementing UI messages and UI message handling code can be found here