How to make the field U D Code mandatory in Tcode QA11

Hello All,

In TCode QA11, when the UD Code is left blank, I need to issue an error message stating that it is a required field and later make that field to be editable. I've tried to use BADI implmentation CL_IM_INSPECTIONLOT_UPDAT

method: IF_EX_INSPECTIONLOT_UPDATE~SET_UD_AT_SAVE. Currently I can get the error message by writing:

IF ud_data-vcode = space.

   Message 'UD is mandtory field' TYPE 'S' Display Like 'E'.

ENDIF.

First time after the error message the field UD is editable, but if the user clicks on save again, the field becomes non-editable. Is there any other way to achieve this. I want to have the error message and the control should return back to the field. The user should only be allowed to save once they enter any value to this field.

I've also tried using :

EXIT_SAPMQEVA_007

EXIT_SAPMQEVA_010

But not getting the desired result.

Thanks,

Roshni