Description: Runs the TabSheet's default formula when the page is shown in DBForm Edit mode.
Execution: The DBForm recalculates before the formula and again afterward. The second recalculation occurs after both successful and failed calculation. The event does not execute in Design mode or other non-Edit modes.
Desktop: The VCL TabSheet OnShow event invokes the formula when the page becomes active.
Web: A user tab change invokes the inherited show handler for the active page. During initial DBForm show processing, the web implementation separately invokes the event for every visible web TabPage; it does not explicitly restrict this pass to the active page. A formula must therefore tolerate an initial call for multiple visible tabs.
Arguments: There are no event-specific arguments. The direct script call does not populate the common event arguments.
Result: Any value assigned to Result is ignored. Use the formula to refresh or initialize data displayed on the page.
Example:
ShowMessage("The tab page is being shown");