I/O field grayed out after check box checked ( Dynpro)

Question

Hi ,
I have dynpro  dialog screen  with several check boxes linked with input/output field
When check box is checked the I/O field is editable when check box is empty I/O field should be grayed out.
I am trying to find the way how checking the check box can trigger the change of attribute of I/O field.
The IO field should be gray out after checking check box without hitting enter or any other button.
Please advice
Chris

Answer 1

Hi ,
Thank you for your answer. I was missing Functional code of my check boxes.
Now i have still issue my I/O field do not turns in gray ( only output) In loop
I dide like you said ( this is example from my PAI module user-command)
when 'CB1'.
      loop at screen .
        if screen-name = 'LT_FORMAT_IO'
          and lt_format_cb is initial.
          screen-input = '0'.
          screen-invisible = '1'.
          modify screen.
        endif.
      endloop..
Once screen is displayed again , the IO field stll remains non grayed out.
Please advice
Chris