Modifying property sheet templates on Win95

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This code is written to fix the bug in CPropertySheet::DoModal() or
CPropertySheet::Create() as described in MSKB article ID: Q158552.

The description of the bug:

(This bug is present for comctl32.dll version <4.70 and Windows95.) When a property sheet displays its property pages, it has to modify their templates. It tries to write into the memory; that works under Win32s (because the resources are writable) and it works under WinNT (because BeginResourceUpdate exists) but it fails under Win95 and raises an Access Violation. If you are not working with exceptions (try/catch(...), __try/__except, _set_se_translator) everything's OK - the OS gets the exception, unlocks the resources (or copies them to writable memory). However, if you're trying to be a good programmer and you add some code to your app to catch OS exceptions you are in a deep trouble.

The suggested fix #1 in the KB article (make the .rsrc section
writable) is OK but error-prone. It is not a very aestheticly pleasing
solution either.

The suggested fix #2 in the KB article is nonsense – or I didn’t
understand correctly what it says.

The suggested fix #3 is unusable if you want to have
__try/__except. Also, you can’t catch access violations when the
property sheet is active.

In this article, I offer another solution: I created a
CSafePropertyPage class based on CPropertyPage. The one and only
difference is that this modified property page uses a (potentially
writable) copy of a dialog template instead of just using resource
ID. It uses undocumented MFC class CDialogTemplate (defined in
afxpriv.h) but you may look up the source code of CDialogTemplate and
supply your own CDialogTemplate::Load if you desperately want to keep
the documented/undocumented paradigm of MFC.

Attached are the source files – just include the header where you
need it and use CSafePropertyPage anywhere you’d use CPropertyPage.

Last updated: 30 June 1998

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