Exception Assistant dialog box doesn't appear when debugging in VB2008 express

Exception Assistant dialog box doesn't appear when debugging in VB2008 express by amajors

Closed

as External Help for as External

Type:	Bug
ID:	325742
Opened:	1/31/2008 12:40:22 PM
Access Restriction:	Public

Workaround(s)

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User(s) can reproduce this bug

Using Visual Basic 2008 express.
Running the example code from "Ouch! My program didn't like that!..." illustrating the use of the exception assistant dialog, the dialog fails to appear and the program being debugged hangs. This occurs if the solution target is anyCPU. Setting target to x86 results in normal behavior. Host OS is Vista x64

Details (expand)

English

Visual C#, C++, J#, or Visual Basic Express

Windows Vista

English

Run on Vista 64 bit.
Create a windows forms application using default solution target of anyCPU. In the form load event, enter code which creates an exception, for example, divide by zero. run in debug mode.

An exception will be reported in immediate window, but no dialog will appear.

exception assistant dialog should appear pointing to the line at which the divide by zero occurred.

File Name	Submitted By	Submitted On	File Size
snapshot_kylin_Vista.jpg	Microsoft	1/31/2008	103 KB
hangs_while_debugging.jpg (restricted)	amajors	2/1/2008	-
divbyzero.zip (restricted)	amajors	2/1/2008	-

Posted by Microsoft on 2/15/2008 at 10:41 AM

Thank you to report this issue.

This is a known issue on 64-bit OS platform. The reason is that the 64bit OS core does not allow user mode exception through kernal mode stacks. The exception is swallowed by OS sliently. That happens in FormLoad handler, because it is called in an OS callback. 32bits OS doesn't do this, so it doesn't repro there.

The OS team is investigating related issues. In the mean time, you do have to work around this issue. Turning on "Stop on first chance exception" will make the debugger to stop in this scenario. But it does make the debugger to stop very often, so you might want to do this only when you find a problem.

Thank you

Posted by Microsoft on 2/14/2008 at 12:46 AM

Thanks for your response. We are escalating this issue to the appropriate group within the Visual Studio Product Team for triage and resolution. These specialized experts will follow-up with your issue.

Thank you,
Visual Studio Product Team

Posted by amajors on 2/1/2008 at 6:10 PM

I created a new project to ensure the error was reproducible. I'll attach a zip of the project and a snapshot of the IDE waiting for the dialog that never appears. Note that the exception is correctly reported in the immediate window, but no exception assistant dialog. I know I've seen it for other exceptions, so this is puzzling.

Posted by Microsoft on 1/31/2008 at 9:51 PM

Thanks for reporting the issue.
In order to fix the issue, we must first reproduce the issue in our labs. We are unable to reproduce the issue with the steps you provided. See attached snapshot.
It may help if you provide us with:

1. a demo project.
2. more snapshots.

If we do not receive a response from you after 7-days , we will automatically close your issue. There is no obligation to respond -- at any time you may edit your issue via Connect and change the status to “Active.”

Thank you,
Visual Studio Product Team