VNC SC compatibility With WPF project

[framidev]

Hello,
I'm a programmer, working on a C# DotNet3 WPF application, and I've encountered a big problem with my application, during a VNC SC assistance.

My application encounters an exception, which leads to a Microsoft Application Error, when I'm running VNC SC on the same computer, BUT ONLY since the 2009 version of VNC SC (new SCHook.dll apparition? winvnc.exe?). So it is not crashing with the older versions. Moreover, it only crashes on XP OS (not on Seven).

The crash seems to appear when my application is loading a (Styled) TabItem which contains a WindowsFormHost (many hours of investigations !).

Are you aware of such kind of crash?
Do you want me to send you an example of WPF application which crashes?

Thanks for your help,

Antoine.

[JDaus]

firstly, I'm not a uvnc dev, so I will not be able to help you solve the problem, but I think you need to explain a little bit more, so that the devs can better assist you.

1, how are you using sc, is it integrated into your app, or are you just using sc to support your app.

2, is the crash happening after a set period of time, randomly, or can you get it to crash every time, by doing a certain thing ? (if you can supply sample code / app that causes this error, that would be best.

3, if you incorporated sc into an app, post a link so we can see where its being used. most devs like that sort of thing ...
if you didn't incorporate into your app, have you tried scprompt or chunkvnc?

[framidev]

Hello JDaus,
First of all, thanks for your answer.

I can give you some details.

1 - I'm using sc with my customers to support my app.


2 - the app crashes every time I do the following thing :
* sc is launched on the customer computer.
* My app (just a WPF Windows, containing 5 Tabs) is launched.
* All the tabs are empty or not, except the "tab 4", which just contains a
WindowsFormHost object.
* I can navigate in all tabs, except the 4 one.
* My app crashes at the moment I click on the "tab 4" (graphically loading the tab).
* The crash appears if i'm doing the manipulation, and ALSO if the customer do, while i'm watching with sc.
* Since the moment sc is deconnected, the customer can navigate in all tabs without crashing.

The original example app source can be downloaded from the following website :
http://www.blogs.intuidev.com/post/2010 ... rtOne.aspx

I've just added an empty WindowsFormHost object in the fourth tabs of these apps, and it crashes in the case where there are styles.

-> email or PM me if you want the link to download my app, and my SC versions


3 - Concerning the used softwares and environment,
* I didn't test with scprompt or chunkvnc
* My app doesn't crashes with an older version of VNC SC
* My app doesn't crashes if running on Windows 7 OS.

Thanks again !

Antoine.

[framidev]

Hello again,
please find the stacktrace, provided by VS2009 when crashing :

Code: Select all

Message="Value cannot be null.\r\nParameter name : el"
  Source="UIAutomationProvider"
  ParamName="el"
  StackTrace:
       à System.Windows.Automation.Provider.AutomationInteropProvider.ReturnRawElementProvider(IntPtr hwnd, IntPtr wParam, IntPtr lParam, IRawElementProviderSimple el)
       à System.Windows.Forms.Integration.WindowsFormsHost.OnWmGetObject(IntPtr wparam, IntPtr lparam)
       à System.Windows.Forms.Integration.WindowsFormsHost.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       à System.Windows.Interop.HwndHost.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       à MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       à System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
       à System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       à System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       à System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter)
       à System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
       à MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       à MS.Win32.UnsafeNativeMethods.ITfMessagePump.GetMessageW(MSG& msg, Int32 hwnd, Int32 msgFilterMin, Int32 msgFilterMax, Boolean& result)
       à System.Windows.Threading.Dispatcher.GetMessage(MSG& msg, IntPtr hwnd, Int32 minMessage, Int32 maxMessage)
       à System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       à System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
       à System.Windows.Threading.Dispatcher.Run()
       à System.Windows.Application.RunDispatcher(Object ignore)
       à System.Windows.Application.RunInternal(Window window)
       à System.Windows.Application.Run(Window window)
       à System.Windows.Application.Run()
       à Multitest.App.Main(String[] args) dans C:\Projets\Multitest\App.xaml.cs:ligne 31
       à System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       à System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       à Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       à System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       à System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       à System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Thank you,

Antoine.

[adzm]

I will be looking into this as well.

Please send me the source of an app that has the issue.

adam.walling@gmail.com

[framidev]

FYI,
if the project is targetting .NET 4, it works...

Adzm can easily see the bug via Reflector, but is not sure there's an alternative.

You can see here :

http://connect.microsoft.com/VisualStud ... pplication