I created a new Windows Store app project using the Grid App (XAML) template. I ran the project (in debug mode) without changing a single line of code. While it was running, I switched back to Visual Studio and clicked the Suspend button in the toolbar.
At this point, the app threw a SuspensionManagerException. The exception’s details weren’t too helpful. The message is SuspensionManager failed. It has the (so far) unhelpful HResult -2146233088. It also has an InnerException that’s just as unhelpful. Its message is Error HRESULT E_FAIL has been returned from a call to a COM component. and its HResult, which is -2147467259, is even worse than the outer exception’s HResult.
The line of code that throws the exception is in the SuspensionManager, which, again, is part of the project template. Here’s the line:
StorageFile file = await ApplicationData.Current.LocalFolder.CreateFileAsync(sessionStateFilename, CreationCollisionOption.ReplaceExisting);
The part that triggers the exception is LocalFolder.CreateFileAsync(…). The MSDN documentation for the CreateFileAsync method has a “Remarks” section that reads: If you try to create a file in a virtual folder like a library or a file group, this method may fail.
That’s it. There’s no explanation of why it may fail, or a description of the conditions under which it may fail, or what you can do about it.
As it happens, even when it fails, the file is actually created. The file in question is called _sessionState.xml and is located at C:\Users\<username>\AppData\Local\Packages\<package_id>\LocalState. If I delete the file and re-suspend the app, the exception is throw again and the file is recreated.
I've searched high and low and haven't found anything conclusive. The CreateFileAsync method is a projection, so I can't easily disassemble it or figure out why it "may fail".
Does anybody have any idea what could be causing this problem, or how to go about debugging or solving it?
The first thing to check is that Frame.Navigate should only take primitives as its parameter argument.
Also, make sure you are calling GetDeferral in your async event handler.
Related
I am attempting to port the DirectX12/XAML UWP template over to a C++-WinRT version... where EVERYTHING is done via C++-WinRT and I can turn off CX. I'm currently stuck on how to ResizeBuffers on the swapchain. Before resizing the buffers I have to release all the buffer references. In C++/CX ComPtr there is Reset() method to release reference of the renderTarget buffers, but in C++/winrt com_ptr no such Reset() method exists and if I set renderTarget to nullptr in order to release it, it throws an exception shown in the Screenshot below. And if I don't set the renderTarget to nullptr then exception is not thrown but the swapChain is also not resized.
Later I also tried it using the wrl::ComPtr and the Reset() method it is still throwing the same error. Does anyone know the correct way of resizing the swapChain in DirectX12?
Screenshot of the code and error
You can't use a "fail-fast" error handler like ThrowIfFailed for ResizeBuffers or Present. Both return meaningful failure codes at runtime you must handle.
Specifically both can return DXGI_ERROR_DEVICE_REMOVED or DXGI_ERROR_DEVICE_RESET and you need to handle it. In fact, in the UWP environment, you will see this happen at start up so you must handle it--some 'classic' Win32 desktop apps just ignore it and crash at weird times like when Windows Update updates a driver while the game is running.
For details on handling 'lost-device' (which is really 'device removed'), see DeviceResources .h / .cpp.
See also Microsoft Docs which is written for DirectX 11, but all the equivalent stuff has to happen for DirectX 12.
In Google Play Console on the dashboard of your application there
is a graph with Crashes & ANRs.
What is the best practice to solve
crashes to provide the best service to your users? My application is
written in Python in Kivy framework.
Navigate to Quality -> Android Vitals -> Crashes and ANRs.
This lists each event and on the right you will see a "->" arrow labelled "View Details".
Click this, scroll down past the graph and you'll see the Stack traces.
This is what you need to look at to fix your code.
The top line will be the error, then it'll show the line of code where the error occurred, for example:
[code]
java.lang.NullPointerException:
at com.test.MyApp.doSomethingCool (MyClass.java:123)
at com.test.MyApp.somethingElse (AnotherClass.java:321)
[/code]
Here you have some null value causing an issue in the "doSomethingCool" function of your app and that code should be on line 123 of "MyClass.java".
The trace lines after that show what called that function that failed, so above, this is showing that "doSomethingCool" was called from function "somethingElse" on line 321 and that code is in "AnotherClass.java".
This example is for Java.
--Updated--
If you are coding in Python, then the stack trace may not show you where in your own code the problem lies. Instead your best bet is to search on Google for the top line error and hope that the answer is online.
Separately from stack trace analysis I would highly recommend that you place your project into source control with GIT or SVN, specifically so that you can see what changes might have caused an error.
Update your code in the repository only when it's working and then you will always have a safe saved version that is known as working. You can then easily compare your current code and see what changes might have caused an error. This is especially useful for Android, which regularly updates versions of shared libraries.
First I will describe the crash types I know about. Scroll down for the actual question. Note that I am only interested in crashes that are handled by Windows. Specific applications and frameworks sometimes have their own crash handlers (eg. Cygwin, the VCL, Java or .NET), which I will not discuss.
Dr Watson
On Windows XP, most unhandled "Structured Exceptions" such as access violations produce a Microsoft Application Error Reporting dialog (it was later renamed "Windows Error Reporting" but the executable is dwwin.exe and I will call it Dr Watson):
It is easily reproduced with *(char*)0=0;
FatalAppExit
Calling FatalAppExit() produces a MessageBox and Event Log entry, but no Dr Watson:
Stack overflow
On Windows XP a stack overflow causes the process to unceremoniously exit with no notification at all. (I think this was fixed starting with Vista)
It can be reproduced with main(){main();}
My question is, what causes one of these:
This dialog is owned by csrss.exe, and by the time I see it, the AcroRd32.exe process has exited.
It also writes an entry in the System Event Log (which a Dr Watson crash doesn't do):
I can reproduce the dialog and Event Log entry (but obviously not an actual crash), with this call to MessageBox:
MessageBox(
0,
"The exception unknown software exception (0xc0000409) occurred in the application at location 0x00404def.",
"AcroRd32.exe - Application Error",
MB_ICONSTOP | MB_SERVICE_NOTIFICATION);
I've ruled out Adobe Reader running as a service. It is version 11.0.08. The crash seems to happen sporadically when a Windows Explorer window with a PDF file selected becomes the active window.
Of course I'm not asking you to troubleshoot Adobe Reader for me, just how to produce an "Application Error" / "Application Popup" type of crash, preferably programmatically so I can understand what's going on.
This looks like the work of kernel32.UnhandledExceptionFilter. You might be able to trigger this error message with:
EXCEPTION_RECORD Rec = {
ExceptionCode : 0xc0000409, /* STATUS_STACK_BUFFER_OVERRUN */
ExceptionAddress : cast(void*) 0x404def,
};
CONTEXT Ctx;
RtlCaptureContext(&Ctx);
EXCEPTION_POINTERS Xcep = {
ExceptionRecord : &Rec,
ContextRecord : &Ctx,
};
UnhandledExceptionFilter(&Xcep);
However on Windows 7 that didn't do it for me, it just went straight to Dr Watson.
What does seem to work on W7 is this:
size_t[2] Params = [
0xc0000409, /* STATUS_STACK_BUFFER_OVERRUN */
0x404def, /* exception address */
];
int Response;
NtRaiseHardError(
0xc0000144 /* STATUS_UNHANDLED_EXCEPTION */ |
0x10000000 /* HARDERROR_OVERRIDE_ERRORMODE */,
Params.length,
0, /* UnicodeStringParameterMask */
Params.ptr,
2 /* OptionOkCancel */,
&Response
);
I know UnhandledExceptionFilter has this code somewhere, I just don't know what conditions it needs to take that code path. But you can just call NtRaiseHardError like this yourself.
Here's the result:
I don't use XP any more so you'll have to experiment yourself to see how these methods behave on XP, but hopefully this will give you a starting point.
The error dialog owned by CSRSS (which can also be programmatically triggered by a manual call to NtRaiseHardError, see this answer), is displayed on Windows when you have an unhandled exception. For all Win32 applications, a default exception handler for unhandled exceptions is set up by kernel32.dll, and this is this handler that does the job of either showing the Windows Error Reporting dialog, or showing the error dialog.
For the details, the open-source ReactOS project (which aim is to "re-create" Windows in an open-source way using clean-room RE) has similar code, that should help you knowing precisely in which conditions the error dialog appears: see the UnhandledExceptionFilter() function in dll/win32/kernel32/client/except.c.
I have two page application and the main page is default is "MainPage.xaml" and the second one is "AddPerson.xaml" when user click a button on main page I want the app to take user to "AddPerson" page.
And I wrote following for the Click event of the button
Me.Frame.Navigate(System.Type.GetType("AddPerson.xaml"))
and I am getting the following error
An exception of type 'System.NullReferenceException' occurred in MedicineSchedule.exe but was not handled in user code
Additional information: Object reference not set to an instance of an object.
If there is a handler for this exception, the program may be safely continued.
I tried other method of navigationservice.navigate which I cannot find the class in VS2013 express at all. The only method available is Me.Frame.Navigate in my project, please let me know how I can get this simple thing to work.
If it was .net 2.0 I would simple called new form with form.lod or something similar.
This doesn't work?
this.Frame.Navigate(typeof(AddPerson));
If you want/have to use a string take a look at the reply here:
convert string to type of page
I am writing an editor based on xtext. (v 2.2.1)(Eclipse Indigo)
I have a class that extends DefaultLinkingServic and overrides the method:
public List getLinkedObjects(EObject context, EReference ref, INode node) throws IllegalNodeException.
The method throws IllegalNodeException when an object cannot be resolved.
When the exception is thrown (and it should be thrown) the error is not only written to the error log, but it causes a popup window to appear with the error:
An internal error occurred during: "Xtext validation".
org.eclipse.xtext.linking.impl.IllegalNodeException: Action App.f is not applicable for the specified arguments.
This is very problematic especiallyif the file has multiple errors which makes it impossible to edit anything in the editor, since the popup repeatedly appears on screen.
This problem is consistent in several IDE's but in others is not reproducible.
Any help would be greatly appreciated.
You are stumbling accross this bug which was already fixed for 2.3 (due June).
As a workaround, you may want to bind a custom implementation of the LazyLinkingResource and catch the IllegalNodeException in #getEObject. Alternativley you could return an empty list from your custom LinkingService instead of raising an IllegalNodeException.