AT PF##.
This statemet defines an event block whose event is triggered by the
ABAP runtime environment during
list display - provided the screen cursor is on a list line and a function is selected using the function
code PF##. Here ## stands for a number between 01 and 24. In the=
standard list status, these function codes are assigned to the function keys of the input device.
Instead of AT PF## , AT USER-COMMAND should always be used and special function codes should be assigned to the required function keys.