MFC, Sending a message from VB-app to VC-app

Morten Stran
#1 / 4

Sending a message from VB-app to VC-app

--------------9BEE2FC75B12CF524A8A207B
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

How can I send a user defined message containing text from a VB-app to a
VC-app?
My code is shown below, but I don't get the string over. It is just
empty. Any ideas ?

VB-app:
Global Const WM_USER = 1024
Global Const WM_USER_VBDATA = WM_USER + 63
Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal
hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByRef lParam As
String) As Long
Dim par As String

.
.
Private Sub cmdSend_Click()

Dim hWndLoc As Long
hWndLoc = FindWindow("Afx:400000:8:14de:0:3f37", 0)
par = "Test"
SendMessage hWndLoc, WM_USER_VBDATA, 0, par
End Sub

VC-app:
LRESULT CMyMainFrame::USERVbData(WPARAM wParam, LPARAM lparam)
{
char *str = (char *)lparam; // <<<<<The str becomes empty here
return (LRESULT) TRUE;

Quote:

}

--------------9BEE2FC75B12CF524A8A207B
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit

<HTML>
How can I send a user defined message containing text from a VB-app to
a VC-app?
 My code is shown below, but I don't get the string over. It is just
empty. Any ideas ?

VB-app:
 Global Const WM_USER = 1024
 Global Const WM_USER_VBDATA = WM_USER + 63
 Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal
hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByRef lParam As
String) As Long
 Dim par As String

.
 .
 Private Sub cmdSend_Click()
  
     Dim hWndLoc As Long
     hWndLoc = FindWindow("Afx:400000:8:14de:0:3f37",
0)
     par = "Test"
     SendMessage hWndLoc, WM_USER_VBDATA, 0, par
 End Sub

VC-app:
 LRESULT CMyMainFrame::USERVbData(WPARAM wParam, LPARAM lparam)
 {
     char *str = (char *)lparam;    //
<<<<<The str becomes empty here
     return (LRESULT) TRUE;
 }
  </HTML>

--------------9BEE2FC75B12CF524A8A207B--

Mon, 01 May 2000 03:00:00 GMT

LucaGL
#2 / 4

Sending a message from VB-app to VC-app

This is a multi-part message in MIME format.

------=_NextPart_000_0047_01BCF11E.68B77E20
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Dear Morten,
you need to send the lParam as Any.
What Visual C++ is expecting is a location in memory where to find the =
string. not the string itself.

How can I send a user defined message containing text from a VB-app =
to a VC-app?=20
My code is shown below, but I don't get the string over. It is just =
empty. Any ideas ?=20
VB-app:=20
Global Const WM_USER =3D 1024=20
Global Const WM_USER_VBDATA =3D WM_USER + 63=20
Declare Function SendMessage Lib "User32" Alias "SendMessageA" =
(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByRef =
lParam As String) As Long=20
Dim par As String=20
=20
.=20
.=20
Private Sub cmdSend_Click()=20
=20
Dim hWndLoc As Long=20
hWndLoc =3D FindWindow("Afx:400000:8:14de:0:3f37", 0)=20
par =3D "Test"=20
SendMessage hWndLoc, WM_USER_VBDATA, 0, par=20
End Sub=20
=20
=20
VC-app:=20
LRESULT CMyMainFrame::USERVbData(WPARAM wParam, LPARAM lparam)=20
{=20
char *str =3D (char *)lparam; // <<<<<The str becomes empty =
here=20
return (LRESULT) TRUE;=20
}=20
=20
=20

------=_NextPart_000_0047_01BCF11E.68B77E20
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>

<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.71.1712.3"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV>Dear Morten,</DIV>
<DIV>you need to send the lParam as Any.</DIV>
<DIV>What Visual C++ is expecting is a location in memory =
where to=20
find the string. not the string itself. </DIV>
<DIV> </DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; PADDING-LEFT: =
5px">

<<A=20
=

c.no</A>>...</DIV>How=20
can I send a user defined message containing text from a VB-app to a =
VC-app?=20
 My code is shown below, but I don't get the string over. It is =
just=20
empty. Any ideas ?=20
VB-app: Global Const WM_USER =3D 1024 Global Const =

WM_USER_VBDATA =3D WM_USER + 63 Declare Function SendMessage Lib =

"User32" Alias "SendMessageA" (ByVal hwnd As =
Long, ByVal=20
wMsg As Long, ByVal wParam As Long, ByRef lParam As String) As Long =
 Dim=20
par As String=20
. . Private Sub cmdSend_Click()   =
    =20
Dim hWndLoc As Long     hWndLoc =3D=20
FindWindow("Afx:400000:8:14de:0:3f37", 0) =
    =20
par =3D "Test"     SendMessage hWndLoc, =

WM_USER_VBDATA, 0, par End Sub  =20
VC-app: LRESULT CMyMainFrame::USERVbData(WPARAM =
wParam, LPARAM=20
lparam) {     char *str =3D (char=20
*)lparam;    // <<<<<The str becomes =
empty=20
here     return (LRESULT) TRUE; }  =20
</BLOCKQUOTE></BODY></HTML>

------=_NextPart_000_0047_01BCF11E.68B77E20--

Tue, 02 May 2000 03:00:00 GMT

MCS
#3 / 4

Sending a message from VB-app to VC-app

the strings sent by VB are by default BSTR's where alternate characters are
null terminated you need to handle BSTR's and convert to Ctype strings in
your app;
--

Raejsh Parikh - Microsoft Certified Solution Developer
Madras - India
Voice : 91 (44) 642360

======================================================
To get MFC / ACTIVEX / ATL work done by MCSDs for

======================================================

Quote:

> >How can I send a user defined message containing text from a VB-app to a
> >VC-app?
> >My code is shown below, but I don't get the string over. It is just
> >empty. Any ideas ?

> I believe that Windows can only do the clever work of copying data
> between processes for those specific Windows messages that it knows
> might want to do that. For a user defined message it doesn't know that
> you want to pass a string, therefore it won't copy the string between
> processes.

> Have a look at the more general purpose WM_COPYDATA message instead.

> Dave
> ----
> Address is altered to discourage junk mail.
> Remove ".---" for the real address.

Fri, 05 May 2000 03:00:00 GMT

Jeff Koh
#4 / 4

Sending a message from VB-app to VC-app

When passing a string to an API from VB, you need to pass the string
ByVal, not ByRef. With strings passed ByRef, VB will pass a pointer
to the BSTR that VB is using. When you pass a string ByVal to an API,
VB will create a temporary LPSTR (i.e. ANSI) and pass that to the
API. Then when the API returns it will copy the LPSTR back into the
internal BSTR.

--
Jeff Kohn
ORCA Technologies, INC
jkohn "at" orca "dot" net

Quote:

> How can I send a user defined message containing text from a VB-app
to a
> VC-app?
> My code is shown below, but I don't get the string over. It is just
> empty. Any ideas ?

> VB-app:
> Global Const WM_USER = 1024
> Global Const WM_USER_VBDATA = WM_USER + 63
> Declare Function SendMessage Lib "User32" Alias "SendMessageA"
(ByVal
> hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByRef
lParam As
> String) As Long
> Dim par As String

> .
> .
> Private Sub cmdSend_Click()

> Dim hWndLoc As Long
> hWndLoc = FindWindow("Afx:400000:8:14de:0:3f37", 0)
> par = "Test"
> SendMessage hWndLoc, WM_USER_VBDATA, 0, par
> End Sub

> VC-app:
> LRESULT CMyMainFrame::USERVbData(WPARAM wParam, LPARAM lparam)
> {
> char *str = (char *)lparam; // <<<<<The str becomes empty
here
> return (LRESULT) TRUE;
> }

Sun, 14 May 2000 03:00:00 GMT