Passing COM Object -> GPF

[Marc Giesmann]

Hi! I explored the forums about this riddle, but I didn't get an real answer how to do this...

Main Question:
How to pass a COM Object (DISPATCH) to a function? In this code example it's just causing a GPF on the first call/get/let of the oDocument.
In this case I use PB 8.03.

FUNCTION XML_Validate(BYVAL oDocument AS DISPATCH, lWithMSGBOX AS LONG) AS LONG
   LOCAL oErrDoc AS DISPATCH
   LOCAL sErrBuff AS STRING

   LOCAL sLine,sErrCode,sLinePos,sURL,sSource,sReason AS STRING
   LOCAL vRes AS VARIANT
   LOCAL vErrDoc AS VARIANT

   OBJECT GET oDocument.Validate() TO vErrDoc

   SET oErrDoc = vErrDoc

   IF ISFALSE ISOBJECT(oErrDoc) THEN
      MSGBOX "Object wasn't initialized!Error in '" + FUNCNAME$ + "'.",%MB_ICONERROR OR %MB_TASKMODAL,"Internal XML-Error"
      FUNCTION = %FALSE
      EXIT FUNCTION
   END IF

   'Error=
   OBJECT GET oErrDoc.ErrorCode TO vRes
   sErrCode = STR$(VARIANT#(vRes))

   IF ISFALSE lWithMSGBOX THEN
      FUNCTION = VAL(sErrCode)
      EXIT FUNCTION
   END IF

   'Error -> Error Handling.
   IF VAL(sErrCode) THEN
      OBJECT GET oErrDoc.URL TO vRes
      sURL = VARIANT$(vRes)

      OBJECT GET oErrDoc.LINE TO vRes
      sLine = STR$(VARIANT#(vRes))

      OBJECT GET oErrDoc.SRCTEXT TO vRes
      sSource = VARIANT$(vRes)

      OBJECT GET oErrDoc.REASON TO vRes
      sReason = VARIANT$(vRes)

      OBJECT GET oErrDoc.LINEPOS TO vRes
      sLinePos = STR$(VARIANT#(vRes))

      sErrBuff = "The XML-error " + sErrCode + " happend, while parsing '" + sURL + "'." + $CRLF+_
                 "Line" + sLine + ",Collumn " + sLinePos + "." + $CRLF + $CRLF + _
                 sReason

      MSGBOX sErrBuff,%MB_TASKMODAL OR %MB_ICONERROR, "XML-error while revalidating the document."
      FUNCTION = VAL(sErrCode)
   ELSE
      'Everything OK
      FUNCTION = %TRUE
   END IF
END FUNCTION

Best regards,
Marc Giesmann

[Edwin Knoppert]

Set the dispatch in a variant, pass the variant, set it to a local dispatch var again.

[Marc Giesmann]

Is there no other way- something like dimming the DISPATCH variables as Msxml2DOMDocument40
before passing to the function or something like that?

I remember that all this worked fine in some strange way, one or two years ago without the whole variant-converting stuff. I didn't change anything in my XML include since then, but now the same code is forcing GPFs.

Confusing

Maybe I used it another way like, but I don't have the sourcecode anymore where I used it. Only this include left from that time.

Thanks for replying Edwin, I'll convert every function to something like a VARIANT- wrapper.

Best regards,
Marc Giesmann

[Fred Harris]

Byval ?

I don't seem to recall ever having trouble with this with either 8 or 9. I see you have a Byval over-ride in front of the DISPATCH variable. Does this same problem occur with a default Byref pass?

[Marc Giesmann]

Fred,
thanks for having some thoughts about my problem.

To answer your question: Yes =/
BYREF,BYVAL all the same.

Like I said: Very strange...

[Edwin Knoppert]

Afaik passing a dispatch object var is prohibited?
I never pass them directly.

I often pass them via a macro which passes the varptr() and set a local dispatch var again.
A dispatch var is a 'simple' dword in fact.