At Selection Screen Output

We can change selection screen dynamically by the event AT-SELECTION SCREEN OUTPUT. Now SCREEN contains the following fields which hold screen information at run time. We can customize the screen information by looping the screen and modify the screen as required. All screen modifications should be done under the event AT-SELECTION SCREEN OUTPUT.

Component	Length	Type	Attribute	Description
name	132	c	Name	Name
group1	3	c	Group1	Modification group
group2	3	c	Group2	Modification group
group3	3	c	Group3	Modification group
group4	3	c	Group4	Modification group
required	1	c	Required-entry field	Mandatory field
input	1	c	Input	input-enabled field
output	1	c	Output	display field
intensified	1	c	Intensified	intensified field
invisible	1	c	Invisible	invisible element
length	1	x	Visible Length	Field length
active	1	c	Input/Output/Invisible	active field
display_3d	1	c	Two-dimensional	Box
value_help	1	c	Input help	Input help key
request	1	c	-	Input exists
values_in_combo	1	c	Dropdown listbox	Value help exists

In the following example we have called a selection screen where two radio buttons (PO & Item) have been mentioned. PO is selected by default. Now the screen contains four parameters (purchase order, company code, item & material). Now for default selection of PO button the purchase order & company fields are appeared. If we select item button then purchase order, item & material input fields will be displayed.

REPORT  zsr_test.

PARAMETERS: po RADIOBUTTON GROUP rad1 DEFAULT 'X' USER-COMMAND test,
            item RADIOBUTTON GROUP rad1,
            p_ebeln TYPE ekko-ebeln,
            p_bukrs TYPE ekko-bukrs,
            p_ebelp TYPE ekpo-ebelp,
            p_matnr TYPE ekpo-matnr.

AT SELECTION-SCREEN OUTPUT.

  LOOP AT SCREEN.

    "If item is selected then Item field appears
    IF screen-name CP '*P_EBELP*'.
      IF item IS NOT INITIAL.
        screen-active = 1.
      ELSE.
        screen-active = 0.
      ENDIF.
      MODIFY SCREEN.
    ENDIF.

    "If item is selected then Material field appears
    IF screen-name CP '*P_MATNR*'.
      IF item IS NOT INITIAL.
        screen-active = 1.
      ELSE.
        screen-active = 0.
      ENDIF.
      MODIFY SCREEN.
    ENDIF.

    "If item is selected then Company field disappears
    IF screen-name CP '*P_BUKRS*'.
      IF item IS NOT INITIAL.
        screen-active = 0.
      ELSE.
        screen-active = 1.
      ENDIF.
      MODIFY SCREEN.
    ENDIF.
  ENDLOOP.