BUG: "Unspecified error" When Running VB Program That Hosts an ATL Control

• The Microsoft Active Template Library (ATL) 3.0, included with:
  • Microsoft Visual C++, 32-bit Editions, version 6.0
• Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 6.0

SYMPTOMS

When you run a Visual Basic program that contains an ATL ActiveX control, you may get the following error message:

System Error &H80004005 (-2147467259). Unspecified error.

CAUSE

If you created the control using the ATL Object Wizard and added the "HWND" option in the Stock Properties tab, you will get an entry in the .IDL for a [propget] function for the "Window" stock property.

In addition, the property map will contain a PROP_ENTRY(HWND...) macro. When the control is first initialized, the persistence code will go through the property map and call the [propput] functions for each entry via ITypeInfo::Invoke(). Because there is no [propput] function in the .IDL for the Window property, the type library won't have this function, and ITypeInfo::Invoke() will fail.

RESOLUTION

Persisting an HWND doesn't make sense; just comment out the PROP_ENTRY(HWND...) macro in the property map. To prevent this line from being added in the future, remove the following line from Control.h in \Program Files\Microsoft Visual Studio\Common\MSDev98\Template\ATL:

[!if=(SP_HWND, "TRUE")]	PROP_ENTRY("HWND", DISPID_HWND, CLSID_NULL)[!endif] 

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

Additional query words:

Keywords : kbActiveX kbCOMt kbContainer kbCtrl kbCtrlCreate kbPersistSt kbVBp600 kbATL300bug kbGrpMFCATL
Version : WINDOWS:3.0,6.0
Platform : WINDOWS
Issue type : kbbug