How to output a drop-down list in TC

1. screen design
Add the listzknvvvkgrp-Braco drop-down box to the TC drop-down list and select "ListBox with key" as the drop-down type"

2. Define internal tables
* Shard information, used to input help
Data: Begin of itab_vkgrp occurs 0,
Braco like tbrc-Braco,
Vtext like tbrct-vtext,
End of itab_vkgrp.

3. Screen Transaction Processing
Field zknvvvkgrp-Braco module set_data_vkgrp.

4. process module definition

Module set_data_vkgrp input.
Call function 'f4if _ int_table_value_request'
Exporting
Retfield = 'braca'
Value_org = 'S'
Tables
Value_tab = itab_vkgrp
Exceptions
Parameter_error = 1
No_values_found = 2
Others = 3.
If sy-subrc <> 0.
Message ID sy-msgid type sy-msgty number sy-msgno
With sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
Endif.
Endmodule. "set_data_vkgrp Input

5. If you want to call different values multiple times, you can enter the function code in ListBox and trigger it manually (this is not the best method, but it can be achieved)