Hi Pankaj,
You cannot write on selection screen as Every Write statement gets accessed only after START-OF_SELECTION. So, the write statement will not be displayed anywhere on selection screen.
Instead of the same you can use SELECTION SCREEN - COMMENT.
Here the piece of code for your requirement.
SELECTION-SCREEN COMMENT /1(50) comment1 MODIF ID com1.
SELECTION-SCREEN SKIP.
SELECTION-SCREEN COMMENT /1(30) comm2.
SELECTION-SCREEN ULINE /1(50).
PARAMETERS: p_a TYPE i OBLIGATORY.
now , you can set the value of Comment1 and comment2 with the text you want.
for your program you can set value of comment 2 = '1.ABC,/,2.XYZ'.
Hope this will help you.
Regards,
Ashish