Regarding the present thread. Forget about the code attached. Here is the solution code for your requirement. It is tested.
TYPES: BEGIN OF TY_RESB, MATNR TYPE RESB-MATNR, RSPOS TYPE RESB-RSPOS, END OF TY_RESB.
DATA: IT_RESB TYPE TABLE OF TY_RESB, WA_RESB LIKE LINE OF IT_RESB, LV_DISMM TYPE MARC-DISMM.
FIELD-SYMBOLS: <FS_RESB> TYPE ANY.
DATA: BEGIN OF I_RESB OCCURS 100. INCLUDE STRUCTURE RESB.
DATA:END OF I_RESB.
ASSIGN ('(SAPLCOBC)resb_bt[]') TO <FS_RESB>.
I_RESB[] = <FS_RESB>.
SELECT MATNR RSPOS FROM RESB INTO TABLE IT_RESB WHERE AUFNR = CAUFVD_IMP-AUFNR.
CLEAR LV_DISMM.
LOOP AT I_RESB. READ TABLE IT_RESB INTO WA_RESB WITH KEY RSPOS = I_RESB-RSPOS. IF SY-SUBRC = 0. SELECT SINGLE DISMM FROM MARC INTO LV_DISMM WHERE MATNR = WA_RESB-MATNR. IF LV_DISMM = 'P1' OR LV_DISMM = 'P2' OR LV_DISMM = 'P3'. MESSAGE: 'Please check the MRP type of the component materials used' TYPE 'E'. ENDIF. ENDIF.
ENDLOOP.According to this, the Order saving is refused in case the MRP types are P1, P2, P3. This is as per Code line number 25. you customise as per your requirement. In the Order Components tab if any of the materials belong to these 2 MRP types, the following error is thrown in the status bar.
Hope this is of help to you.
Jogeswara Rao K