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VFP 7: Several Apparent Bugs in MSAA Implemention
Message
From
14/09/2001 09:44:37
Ken Dibble
Southern Tier Independence Center
Binghamton, New York, United States
 
 
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Forum:
Visual FoxPro
Category:
Other
Title:
VFP 7: Several Apparent Bugs in MSAA Implemention
Miscellaneous
Thread ID:
00556419
Message ID:
00556419
Views:
64
I have posted a detailed description of these bugs at the microsoft.public.fox.programmer.exchange newsgroup.
I don't want to use up bandwidth reposting it here. I have also reported most of the bugs to Microsoft's VFP Bug
Report site. My concern is that these bugs make VFP 7's MSAA features largely useless and that therefore the
product is neither MSAA compliant nor accessible to users with disabilities. I am asking the MS VFP team to
give this issue top priority and issue a patch ASAP rather than wait for SP 1. That is why I am posting this
notice in as many places as possible.

For those unfamiliar with the issue, MSAA stands for Microsoft Active Accessibility. It is an API that allows
MSAA "servers" to reveal information about the nature and state of their controls and processes, and that
lets MSAA "clients" use that information to provide access to computer users who are blind or have other
disabilities. Earlier versions of VFP did not support MSAA at all; VFP 7 represents the first attempt. That
might justify a more "laid back" attitude if the problems were relatively isolated. However, the problems I have
so far identified make it impossible for the class of MSAA clients called "screenreaders"--which "read" what
appears on the screen and convert it to audible speech--to work correctly with applications developed in VFP.

Apparently, because VFP contains its own controls and does not use standard Windows controls, MSAA has
been implemented differently in VFP 7 than in other MS programming languages. However, I have not been
able to find any documentation that gives specifics about this implementation at the MS site. MSAA
documentation appears to be exclusively directed at C programmers (which I am not). VFP's documentation
concerning MSAA is very sketchy.

I have not done a thorough investigation of all VFP controls' MSAA compliance. However, among the controls
I have investigated and for which I have created reproducible test cases, I have found one C0000005 crash
bug and three controls that do not properly and fully report changes in their "State" to MSAA when they
receive focus when the controls' ControlSource properties are bound to fields in VFP tables. I have also
detected problems related to toolbars that appear to be fiendishly complicated and for which I don't have time
to work on a reproducible test case.

The bugs I have found may not represent the full magnitude of the problem, but I believe they are sufficient to
justify immediate attention.

For a full explanation please see my posts at m.p.f.p.e. Thank you for your attention.
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