Variant as UDT Problem

[Robert Wallace]

Win XP(Prof) SP3 - PBWin 9.01.

I have a problem converting VB6 to PBWin.

Original VB6 Code:

Dim tRange as udtTextRange
...
...
Set oDoc = mySession.ActiveDoc
tRange = oDoc.TextSelection

My Conversion:

GLOBAL tRange AS udtTextRange
...
GLOBAL vtemp as VARIANT
...
OBJECT GET mySession.ActiveDoc TO myDocument

OBJECT GET myDocument.TextSelection TO tRange    ' This produces a "syntax error"

OBJECT GET myDocument.TextSelection TO vtemp     'This compiles
i = VARIANTVT(vtemp)
MSGBOX "textselection_variant = " & HEX$(i)

The .inc file :

TYPE udtTextRange
    beginrange AS udtTextLoc
    endrange AS udtTextLoc
END TYPE
...
...
Property Get TextSelection <297> () As Variant

VARIANTVT(vtemp) returns (From the Help file):
36 Not Listed in Help
Whereas I would expect :
29 %VT_USERDEFINED User Defined Type

Is my conversion wrong?

Bob

[Michael Mattias]

>Dim tRange as udtTextRange
>OBJECT GET myDocument.TextSelection TO tRange

If I've been reading carefully, when you use the dispatch interface via the "OBJECT GET" statement, that always returns a VARIANT, and it's only the "direct" interface which can return a UDT from a property call.

[Robert Wallace]

MCM - Many thanks for the hint (if I remember the time zones you must be working all night!!)

This leaves me between the devil and the deep blue sea - from my previous posts you will see that the first half of my program didn't work if I used a "Direct" interface

[Michael Mattias]

So get the variant... then move the variant to a UDT.

If you can't simply....

  OBJECT GET   .... to vVar
  UdtVar         = vVar

.. then you can

  LOCAL pVar AS VARIANTAPI  PTR 
  OBJECT GET ... to vVar 
  pVar = VARPTR (vVar)

.. and move the data to UDTVar from the detail provided in the VARIANTAPI structure.

[Robert Wallace]

  OBJECT GET   .... to vVar
  UdtVar         = vVar

This produces a "Data Type Mismatch"

  LOCAL pVar AS VARIANTAPI  PTR 
  OBJECT GET ... to vVar 
  pVar = VARPTR (vVar)

.. and move the data to UDTVar from the detail provided in the VARIANTAPI structure.

Haven't a clue how to do the above
(However as vVar isn't returning a UDT as it should then how would I know how to interpret any data even if I knew how to program it.).

Back to VB6 again (inspite of criticisms - for an old program it handles very complex COM beautifully and, infact, with little or no speed difference - only the program size is different)

-----------------------------------------------
Added Later.

Finally understood what MCM was getting at but I still get a VARIANT Type of 36 which seems to be illegal

Bob

[Michael Mattias]

TYPE "36?" That' s not what I get.... I get BSTR ...

TYPE FOO
     X AS LONG
     Y AS LONG
END TYPE


FUNCTION PBMAIN() AS LONG
     
  LOCAL v AS VARIANT, F AS FOO, S AS STRING
  
     F.X =  1234
     F.Y =  5678
      
     LET v  =F
     STDOUT "Variant type =" &  FORMAT$(VARIANTVT(v))  ' returns 8 (bSTR)
     S = VARIANT$(v)
     
     TYPE SET F= S
     STDOUT USING$("X #  Y #", f.x, f.y)
     WAITKEY$

END FUNCTION

==> 

Variant type =8
X 1234  Y 5678

MCM

[Robert Wallace]

' returns 8 (bSTR)

The last thing I would expect it to return - according to the documentation:

8 %VT_BSTR Dynamic String

I would have expected:

29 %VT_USERDEFINED User Defined Type

Bob

[Michael Mattias]

I'm still trying to figure out which types can be combined to make a '36'

Maybe 36 (decimal) is something new.

That, or the whole idea of using the Component Object Model is to get away from returning records as UDTs... i.e., each member of a UDT is supposed to be a property.

MCM

[Robert Wallace]

Maybe 36 (decimal) is something new.

No the tlb dates back to at least 2006.

I am beginning to suspect that it may be a VB6 special and that I will never be able to rewrite in PBWin.

The VB6 code is deceptively simple:

tRange = oDoc.TextSelection

but "TextSelection" returns a Variant and tRange is two UDT's within a UDT - I can't image how VB6 extracts the data from the Variant and puts it into a UDT:confused2:

Unfortunately that single statement is the heart of the program (it defines the beginning and end of a selected text and the current position within a line of text) which enables all the other text handling procedures.

Bob

P.S. I have just read that VB6 will work within Windows 7 for the lifetime of that operating system (I suspect for ever!!)

[Tom Hanlin]

I'm guessing that VT_VOID just specifies that the data is a blob-- some miscellaneous collection of data. VB is probably just stuffing the UDT with the contents of the variant, up to the size of the UDT. You can readily duplicate that approach by something along the lines of:

sInfo$ = PEEK$(VARPTR(vTemp), SIZEOF(vTemp))
sInfo$ = MID$(sInfo$, 9) ' skip to variant data
sInfo$ = LEFT$(sInfo$, SIZEOF(tRange)) ' make sure it's not too long
POKE$ VARPTR(tRange), sInfo$

[Michael Mattias]

> that VT_VOID

But VT_VOID is not 36 decimal.

What the heck is VT_TYPE 36 decimal?

[José Roca]

What the heck is VT_TYPE 36 decimal?

It is %VT_RECORD, an UDT in C++ lingo.

Please, see my post and Dominic Mitchell's post in this thread:

http://www.powerbasic.com/support/pb...hlight=brecord

[José Roca]

You can find information about the IRecordInfo interface here:
http://msdn.microsoft.com/en-us/library/ms221039.aspx

[Michael Mattias]

Excellent description and support code for '36' in linked post!!!

Found this in SDK..

IRecordInfo Interface
IRecordInfo describes the structure of a particular UDT. You can use IRecordInfo any time you need to access the description of UDTs contained in type libraries. IRecordInfo can be reused as needed; there can be many instances of the UDT for a single IRecordInfo pointer.

There's a whole lot more in the SDK article.

That's from my on-disk SDK... while this big test run is executing, let me see if I can find a link to the on-line version at MSDN....yup, here 'tis...

http://msdn.microsoft.com/en-us/library/ms221039.aspx

MCM

[Robert Wallace]

A big Thank You

Many thanks for all your help

Just for the record the following is the final working code

FUNCTION GetPosn (StartPosn AS LONG, EndPosn AS LONG, read_write AS LONG) AS LONG
  LOCAL tRange AS udtTextRange PTR
  LOCAL pv AS VARIANT_STRUCT PTR

  OBJECT GET myDocument.TextSelection TO vtemp
  pv = VARPTR(vtemp)
  tRange = @pv.br.pvRecord
  IF read_write = 0 THEN                       'Read
    startposn = @tRange.beginrange.offset
    endposn = @tRange.endrange.offset
  ELSE                                         'Write
    @tRange.beginrange.offset = startposn
    @tRange.endrange.offset = endposn
  END IF
END FUNCTION

[Robert Wallace]

Next Problem !

The original VB6 code creates tRange which is used for all other text handling:

Dim tRange as udtTextRange
...
...
Set oDoc = mySession.ActiveDoc
tRange = oDoc.TextSelection

I now have to delete the marked text(VB6):

oDoc.TextSelection trange

The Method is:

Method DeleteText <349> (Byval textRange As Variant) As Long

How do I convert the PTR from the previous post:

LOCAL tRange AS udtTextRange PTR

into the form required by the Method?

[José Roca]

You already have it. Pass vTemp.

[Robert Wallace]

You already have it. Pass vTemp

That is what I thought too but the Compiler won't have it:

OBJECT GET myDocument.TextSelection TO vtemp
myDocument.DeleteText vtemp

The cursor is placed in front of vtemp and I get the message:

METHOD or PROPERTY name expected

[Dominic Mitchell]

You are using the Object Call|Get|Set syntax, therefore, change

myDocument.DeleteText vtemp

to

Object Call myDocument.DeleteText(vtemp)

[Robert Wallace]

I am a complete idiot - it works of course