Browse for a file on input parameter using F4 button

Many times we need a drop down button to choose the file that we need for reports or BDC. This tip gives the users a Windows style Browse option to select the file from local PC or the network.

parameters: in_file like rlgrap-filename.

at selection-screen on value-request for in_file.

  clear g_tmp_file_path.
  perform select_input_file_name.
  move g_tmp_file_path to in_file.

form select_input_file_name.
  call function 'F4_FILENAME'
       exporting
            program_name  = sy-repid
            dynpro_number = sy-dynnr
            field_name    = 'PATH'
       importing
            file_name     = g_tmp_file_path.

endform.