PRB: Older MFC OCX Controls Incompatible with Visual Basic 4.0 (168831)
The information in this article applies to:
- Microsoft Visual Basic Standard Edition, 32-bit, for Windows 4.0
- Microsoft Visual Basic Professional Edition, 16-bit, for Windows 4.0
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows 4.0
- Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows 4.0
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows 4.0
This article was previously published under Q168831 SYMPTOMS
Upon placing an OCX control on a Visual Basic form, the control will ASSERT
or cause a General Protection Fault. The most common asserts are as
follows: - Assertion Failure in CTLPROP.CPP Line 768
- Assertion Failure in CTLMODUL.CPP Line 128
The control will continue to run in most cases, but will not function
properly.
CAUSE
OLE Custom Controls (OCX Controls) created using the Microsoft Foundation
Classes (MFC) that ship with Microsoft Visual C++ version 2.0 or earlier
for 32-bit development and Microsoft Visual C++ 1.51 or earlier for 16-bit
development will not work properly in Visual Basic 4.0.
The OCX standards and implementations have changed such that some minor
incompatibilities have been created. The following MFC code raises the
assertion when Visual Basic passes NULL as parameters:
STDMETHODIMPCOleControl::XPerPropertyBrowsing::GetPredefinedStrings(
DISPID dispid,
CALPOLESTR FAR* lpcaStringsOut, CADWORD FAR*
lpcaCookiesOut)
{
...
METHOD_MANAGE_STATE(COleControl,PerPropertyBrowsing)
...
ASSERT_POINTER(lpcaStringsOut,CALPOLESTR);
ASSERT_POINTER(lpcaCookiesOut, CADWORD);
...
}
RESOLUTION
Upgrade to Visual C++ 2.1 or higher for 32-bit development and Visual C++
1.52 or higher for 16-bit development.
STATUS
Microsoft has confirmed this to be a problem with Visual C++ version 2.0
and earlier for 32-bit development and Visual C++ 1.51 and earlier for
16-bit development.
(c) Microsoft Corporation 1997, All Rights Reserved. Contributions by
Troy Cambra, Microsoft Corporation
| Modification Type: | Minor | Last Reviewed: | 7/16/2004 |
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| Keywords: | kbprb KB168831 |
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