How to use MODIF ID at a SELECTION-SCREEN

Question

Hello,
how can use a SELECTION-SCREEN block with MODIF ID? My SELECTION-SCREEN definition looks like the example below and I want to combine it with a MODIF ID - how can I do this?
SELECTION-SCREEN BEGIN OF BLOCK par3 WITH FRAME TITLE text-003.
PARAMETERS:    p_pfadn  LIKE rlgrap-filename
               DEFAULT    '/home/dsbftp/due_test/konditionen_avs3.txt'.
SELECTION-SCREEN SKIP 1.
PARAMETERS:    p_trans  TYPE tcode DEFAULT 'JC03',
               p_appl   TYPE kappl DEFAULT 'J0'.
SELECTION-SCREEN END OF BLOCK par3.
thx

Answer 1

Hi Mike,
To modify the appearance of an input field on the selection screen, you must assign the parameter to a modification group as follows:
PARAMETERS <p> ...... MODIF ID <key> ......
The name of modification group <key> should be a three-character variable name without quotation marks.
The MODIF ID addition always assigns <key> to the SCREEN-GROUP1 column of internal table SCREEN.
Parameters assigned to a modification group can be processed as an entire group with the LOOP AT SCREEN and MODIFY SCREEN statements during the AT SELECTION-SCREEN OUTPUT event.
You can do the following modifications to the selection screen elements:
1) REQUIRED: When you set REQUIRED = 1, a field that is ready for input is made mandatory
2) INPUT: When you set INPUT = 1,  Ready for input, even if Input is not set statically.
3) OUTPUT: When you set OUTPUT = 1, Field is for display only
4) INTENSIFIED: When you set OUTPUT = 1, Field is highlighted
4) INVISIBLE: When you set INVISIBLE = 1, Screen field is not displayed, regardless of the static attributes.
5) ACTIVE: When you set ACTIVE = 1, At the beginning of the PBO, ACTIVE is always set to 1, regardless of the static attribute settings. Setting ACTIVE to 0 automatically sets INPUT = 0, OUTPUT = 0, and INVISIBLE = 1. 
Here is the sample code:
REPORT modif_example.
PARAMETERS: FIELD1(10) MODIF ID FL1,
            FIELD2(12) MODIF ID FL2,
            FIELD3(15) MODIF ID FL3,
            FIELD4(20) MODIF ID FL3.
AT SELECTION-SCREEN OUTPUT.
LOOP AT SCREEN.
  IF SCREEN-GROUP1 = 'FL1'.
    SCREEN-INPUT = '1'.
    MODIFY SCREEN.
    CONTINUE.
  ENDIF.
  IF SCREEN-GROUP1 = 'FL2'.
    SCREEN-INPUT = '0'.
    MODIFY SCREEN.
    CONTINUE.
  ENDIF.
  IF SCREEN-GROUP1 = 'FL3'.
    SCREEN-REQUIRED = '1'.
    MODIFY SCREEN.
    CONTINUE.
  ENDIF.
ENDLOOP.
Hope it helps.
Regards,
Neeraj Gupta