SAP ALV Tutorial 2 – Event
This article deals with event handling in SAP alv and mechanism behind it. In a nutshell, alv Grid is an implementation of custom control. You must be very familiar with the dynpro programming. In dynpro programming, we general have two events: PBO and PAI. If user have some actions in the frontend screen, the event PAI will be triggered and program can have different reactions according to different function codes. In the custom control, things become a slight different. It will trigger an specific event, if user does some actions in the frontend. There are two types of event: system event and application event.
The only difference of the two events are the sequence of triggering event handler method and the PAI event.
System event: A system event is triggered before any automatic field checks (for example,required fields) have taken place on the screen, and before any field transport. The PAI and PBO events are not triggered. Consequently, you cannot access any values that the user has just changed on the screen. Furthermore, there is no field transport back to the screen after the event, so values that you have changed in the event handling are not updated onthe screen.