Obscure Exception in Windows Forms Code

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I have been plagued with seemingly random crashes in my Windows Forms
application. It's hard to pinpoint when the crash occurs bu is often when
minimizing the app or closing it. I am clueless as to what the problem is
and it was happening in 1.0 and now 1.1 framework. I can sort of repro it
by clicking on abunch of things in my app (basically exercise the app a but
and then when I close it the app may or may not crash). This is the closest
I have gotten to a repro. The call stack looks like this:

System.windows.forms.dll!System.Windows.Forms.UnsafeNativeMethods.DestroyWin
dow(System.Runtime.InteropServices.HandleRef hWnd =
{System.Runtime.InteropServices.HandleRef})
system.windows.forms.dll!System.Windows.Forms.NativeWindow.DestroyHandle()
system.windows.forms.dll!System.Windows.Forms.Control.DestroyHandle()
system.windows.forms.dll!System.Windows.Forms.Application.ParkingWindow.Dest
roy()
system.windows.forms.dll!ThreadContext.DisposeParkingWindow()
system.windows.forms.dll!ThreadContext.DisposeThreadWindows()
system.windows.forms.dll!System.Windows.Forms.Application.ComponentManager.S
ystem.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoo
p(int dwComponentID = 1, int reason = -1, int pvLoopData = 0)
system.windows.forms.dll!ThreadContext.RunMessageLoopInner(int reason = -1,
System.Windows.Forms.ApplicationContext context =
{System.Windows.Forms.ApplicationContext})
system.windows.forms.dll!ThreadContext.RunMessageLoop(int reason = -1,
System.Windows.Forms.ApplicationContext context =
{System.Windows.Forms.ApplicationContext})
system.windows.forms.dll!System.Windows.Forms.Application.Run(System.Windows
.Forms.Form mainForm = {VssConnectClient.MainForm})
VssConnectClient.exe!VssConnectClient.MainForm.Main(string[] args =
{Length=0}) Line 474

The exception is this:

A first chance exception of type 'System.NullReferenceException' occurred in
system.windows.forms.dll

Additional information: Object reference not set to an instance of an object

Anybody seen this kind of exception?

Thanks - Joel
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Re: Obscure Exception in Windows Forms Code by VoxCode

VoxCode
Mon Aug 04 00:48:24 CDT 2003

Here is an example of another one this time when alt-tabing to another app.

system.windows.forms.dll!System.Windows.Forms.Application.ComponentManager.S
ystem.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoo
p(int dwComponentID = 1, int reason = -1, int pvLoopData = 0)
system.windows.forms.dll!ThreadContext.RunMessageLoopInner(int reason = -1,
System.Windows.Forms.ApplicationContext context =
{System.Windows.Forms.ApplicationContext})
system.windows.forms.dll!ThreadContext.RunMessageLoop(int reason = -1,
System.Windows.Forms.ApplicationContext context =
{System.Windows.Forms.ApplicationContext})
system.windows.forms.dll!System.Windows.Forms.Application.Run(System.Windows
.Forms.Form mainForm = {VssConnectClient.MainForm})
VssConnectClient.exe!VssConnectClient.MainForm.Main(string[] args =
{Length=0}) Line 474

I am beginning to regret my choice of platform!

Joel

"VoxCode LLC" <support@vssconnect.com> wrote in message
news:%23%236INikWDHA.1872@TK2MSFTNGP12.phx.gbl...
> I have been plagued with seemingly random crashes in my Windows Forms
> application. It's hard to pinpoint when the crash occurs bu is often when
> minimizing the app or closing it. I am clueless as to what the problem is
> and it was happening in 1.0 and now 1.1 framework. I can sort of repro it
> by clicking on abunch of things in my app (basically exercise the app a
but
> and then when I close it the app may or may not crash). This is the
closest
> I have gotten to a repro. The call stack looks like this:
>
>
System.windows.forms.dll!System.Windows.Forms.UnsafeNativeMethods.DestroyWin
> dow(System.Runtime.InteropServices.HandleRef hWnd =
> {System.Runtime.InteropServices.HandleRef})
> system.windows.forms.dll!System.Windows.Forms.NativeWindow.DestroyHandle()
> system.windows.forms.dll!System.Windows.Forms.Control.DestroyHandle()
>
system.windows.forms.dll!System.Windows.Forms.Application.ParkingWindow.Dest
> roy()
> system.windows.forms.dll!ThreadContext.DisposeParkingWindow()
> system.windows.forms.dll!ThreadContext.DisposeThreadWindows()
>
system.windows.forms.dll!System.Windows.Forms.Application.ComponentManager.S
>
ystem.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoo
> p(int dwComponentID = 1, int reason = -1, int pvLoopData = 0)
> system.windows.forms.dll!ThreadContext.RunMessageLoopInner(int reason
= -1,
> System.Windows.Forms.ApplicationContext context =
> {System.Windows.Forms.ApplicationContext})
> system.windows.forms.dll!ThreadContext.RunMessageLoop(int reason = -1,
> System.Windows.Forms.ApplicationContext context =
> {System.Windows.Forms.ApplicationContext})
>
system.windows.forms.dll!System.Windows.Forms.Application.Run(System.Windows
> .Forms.Form mainForm = {VssConnectClient.MainForm})
> VssConnectClient.exe!VssConnectClient.MainForm.Main(string[] args =
> {Length=0}) Line 474
>
> The exception is this:
>
> A first chance exception of type 'System.NullReferenceException' occurred
in
> system.windows.forms.dll
>
> Additional information: Object reference not set to an instance of an
object
>
> Anybody seen this kind of exception?
>
> Thanks - Joel
>
>


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Re: Obscure Exception in Windows Forms Code by Chris

Chris
Mon Aug 04 09:47:54 CDT 2003

We get the same problem (NullReferenceException) using UserControls embedded
in InternetExplorer. We also get SEHException as well as an
ExecutingEngineException, all of which aren't ever supposed to be thrown
since all of our code is purely managed. Probably a bug in the runtime, as
it seems like the underlying engine gets corrupted, as if the runtime is
calling methods on a window that has been destroyed or corrupted somehow.
Help from the MSFT dudes would be nice on this one.

"VoxCode LLC" <support@vssconnect.com> wrote in message
news:OSlBKwkWDHA.1368@TK2MSFTNGP11.phx.gbl...
> Here is an example of another one this time when alt-tabing to another
app.
>
>
system.windows.forms.dll!System.Windows.Forms.Application.ComponentManager.S
>
ystem.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoo
> p(int dwComponentID = 1, int reason = -1, int pvLoopData = 0)
> system.windows.forms.dll!ThreadContext.RunMessageLoopInner(int reason
= -1,
> System.Windows.Forms.ApplicationContext context =
> {System.Windows.Forms.ApplicationContext})
> system.windows.forms.dll!ThreadContext.RunMessageLoop(int reason = -1,
> System.Windows.Forms.ApplicationContext context =
> {System.Windows.Forms.ApplicationContext})
>
system.windows.forms.dll!System.Windows.Forms.Application.Run(System.Windows
> .Forms.Form mainForm = {VssConnectClient.MainForm})
> VssConnectClient.exe!VssConnectClient.MainForm.Main(string[] args =
> {Length=0}) Line 474
>
> I am beginning to regret my choice of platform!
>
> Joel
>
> "VoxCode LLC" <support@vssconnect.com> wrote in message
> news:%23%236INikWDHA.1872@TK2MSFTNGP12.phx.gbl...
> > I have been plagued with seemingly random crashes in my Windows Forms
> > application. It's hard to pinpoint when the crash occurs bu is often
when
> > minimizing the app or closing it. I am clueless as to what the problem
is
> > and it was happening in 1.0 and now 1.1 framework. I can sort of repro
it
> > by clicking on abunch of things in my app (basically exercise the app a
> but
> > and then when I close it the app may or may not crash). This is the
> closest
> > I have gotten to a repro. The call stack looks like this:
> >
> >
>
System.windows.forms.dll!System.Windows.Forms.UnsafeNativeMethods.DestroyWin
> > dow(System.Runtime.InteropServices.HandleRef hWnd =
> > {System.Runtime.InteropServices.HandleRef})
> >
system.windows.forms.dll!System.Windows.Forms.NativeWindow.DestroyHandle()
> > system.windows.forms.dll!System.Windows.Forms.Control.DestroyHandle()
> >
>
system.windows.forms.dll!System.Windows.Forms.Application.ParkingWindow.Dest
> > roy()
> > system.windows.forms.dll!ThreadContext.DisposeParkingWindow()
> > system.windows.forms.dll!ThreadContext.DisposeThreadWindows()
> >
>
system.windows.forms.dll!System.Windows.Forms.Application.ComponentManager.S
> >
>
ystem.Windows.Forms.UnsafeNativeMethods+IMsoComponentManager.FPushMessageLoo
> > p(int dwComponentID = 1, int reason = -1, int pvLoopData = 0)
> > system.windows.forms.dll!ThreadContext.RunMessageLoopInner(int reason
> = -1,
> > System.Windows.Forms.ApplicationContext context =
> > {System.Windows.Forms.ApplicationContext})
> > system.windows.forms.dll!ThreadContext.RunMessageLoop(int reason = -1,
> > System.Windows.Forms.ApplicationContext context =
> > {System.Windows.Forms.ApplicationContext})
> >
>
system.windows.forms.dll!System.Windows.Forms.Application.Run(System.Windows
> > .Forms.Form mainForm = {VssConnectClient.MainForm})
> > VssConnectClient.exe!VssConnectClient.MainForm.Main(string[] args =
> > {Length=0}) Line 474
> >
> > The exception is this:
> >
> > A first chance exception of type 'System.NullReferenceException'
occurred
> in
> > system.windows.forms.dll
> >
> > Additional information: Object reference not set to an instance of an
> object
> >
> > Anybody seen this kind of exception?
> >
> > Thanks - Joel
> >
> >
>
>


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