Thanks for the reply.
However, I couldn't get the results I want. I really want to populate the combo box in the first place, when the program starts running.
But It is empty, unfortunately.
Here is my code snippet:
(defun c:qq ()
(command "_OPENDCL")
(dcl_project_load "modeless")
(dcl_form_show modeless_mainForm)
(dcl-Control-AddList bo_type (list "A" "B" "C"))
(princ)
)