How to validate input's in selection-screen

Question

Hi ,
can any one how to validate input's field's  in selection-screen and each field has diffirent tables and what is the table name which has all the validating fields??
Thank's in advance..

Answer 1

hi,
  You can use validate selct-options using select query by obtaining the realtionship from table .Using the selection-screen events You can write code for validation as follows.
tables:
  kna1.                                " General Customer data
*"Selection screen elements............................................
select-options:
  s_kunnr for kna1-kunnr.              " Customer number
*"Data declarations...................................................
Data declaration of the structure to hold kna1 details              *
data:
  begin of fs_customer,
    kunnr type kna1-kunnr,             " Customer number
    adrnr type kna1-adrnr,             " Address
    anred type kna1-anred,             " Title
    erdat type kna1-erdat,             " Created on
    ernam type kna1-ernam,             " Created by
  end of fs_customer.
*"Constants declarations..............................................
constants
  w_path type string value 'D:\DOWNLOAD\CUSTOMER'.
Internal table to hold customer details                             *
data:
  t_customer like
    standard table
          of fs_customer.
                      AT SELECTION SCREEN OUTPUT                    *
at selection-screen.
  perform retrieve.
Form  RETRIEVE                                                     *
This subroutine retrieve customer data from table kna1             *
There are no interface parameters to be passed to this subroutine. *
form retrieve .
  select kunnr                         " Customer number
         adrnr                         " Address
         anred                         " Title
         erdat                         " Created on
         ernam                         " Created by
    into corresponding fields of table t_customer
    from kna1
   where kunnr in s_kunnr.             " END SELECT
  if sy-subrc ne 0.
    message text-001 type 'E'.
    exit.
  endif.                               " IF SY-SUBRC NE 0
endform.                               " RETRIEVE
regards,
veeresh