What action can be performed to prevent a screen from being loaded until all data is available in OutSystems?

To ensure that a screen does not load until all necessary data is available, employing an On Initialize action is an effective approach. The On Initialize action is triggered when the screen starts loading, allowing developers to execute data retrieval logic before the screen is fully rendered. By placing data fetching logic within this action, you create a prerequisite where data must be gathered before the screen displays its components to the user. This guarantees that when the screen is shown, all expected data is already present and can be utilized effectively.

The other options, while they may affect how data is presented or enhance user experience, do not directly address the problem of preventing the screen load until data is available. For instance, implementing a delay does not ensure that data is ready; it merely pauses the screen loading. Using an AJAX refresh allows for dynamic updating of screen content but is not suitable for initial data loading before rendering the entire screen. Similarly, employing a loading spinner provides a visual cue to the user that data is being loaded, but it does not control the flow of data loading prior to screen display. Hence, the On Initialize action is the most appropriate for this requirement, effectively managing data loading in the Reactive Web application context.