Event Blocks in Executable
Programs
When you run an executable program, the program flow is driven by the external events in the ABAP runtime environment. The following figure shows the sequence of the events:
The events in the gray box are only processed if you have entered a logical database in the program attributes. The AT SELECTION-SCREENevent is only processed if a selection screen is defined in the program or the logical database associated with the program. The other events occur when any executable program is run. (See also Processing Blocks in ABAP Programs.)
As well as these
events, there are others that can, as in other ABAP programs, occur in
executable programs. These occur by default (LOAD-OF-PROGRAM) when lists are created (TOP-OF-PAGE, END-OF-PAGE), and when user actions are performed on
lists (AT LINE-SELECTION, AT
USER-COMMAND). These events
are described under
Classical
Lists.
If you want to handle an event, you must define the corresponding event block in your program. If you do not define the event block, there is no reaction to the event.