AT SELECTION-SCREEN ON p_tage.
DATA: lt_werte TYPE TABLE OF dynpread,
ls_werte TYPE dynpread.
CLEAR: lt_werte, ls_werte.
ls_werte-fieldname = 'P_TAGE'.
APPEND ls_werte TO lt_werte.
CALL FUNCTION 'DYNP_VALUES_READ'
EXPORTING
dyname = sy-cprog
dynumb = sy-dynnr
translate_to_upper = 'X'
TABLES
dynpfields = lt_werte.
READ TABLE lt_werte INDEX1 INTO ls_werte.
IF sy-subrc = 0.
READ TABLE lt_tage INTO ls_tage WITH KEY key = ls_werte-fieldvalue.
IF sy-subrc = 0.
ENDIF.
ENDIF.