Select-option value is not getting captured in at selection-screen on value

In Selection screen , we have Select-option and  a parameter.
Based on the values given in Select-option, the values of Parameter should get populate.
To achieve this functionality,
I  used  At selection u2013screen  on value request  for <parameter>  EVENT and 'F4IF_INT_TABLE_VALUE_REQUEST' Function Module.
But the Select-option values are not getting captured in this event,unless u press Enter key.
Is there any other way to achieve this functionality.
Please Guide me.


When you call function 'F4IF_INT_TABLE_VALUE_REQUEST'. make sure you send it the name of the screen variable - the F4IF_INT_TABLE_VALUE_REQUEST function calls DYNP_VALUES_READ itself if you tell it the name of your report, screen number, and the variable name... snippet below.
    l_repid             type syrepid.
  l_repid = sy-repid.
  call function 'F4IF_INT_TABLE_VALUE_REQUEST'
      dynpprog         = l_repid
      dynpnr           = '1000'
      dynprofield      = 'S_FIELD-LOW'  "Select options - low value
* etc