WP8 Xamarin App hangs on SplashScreen on First start - c#

I have a strange situation. My windowsphone 8 app build with Xamarin and MvvmCross runs perfect from my debugger (visual studio).
Then I submit the app to the app store (beta store by the way). After that I downloaded it on my device and started the app. The splashscreen shows off... but thats it (I waited for about 5 minutes). No crash and no other information about what happens.
When I then go back with my backbutton or my start-button and restart the app. Everything works fine. This situation only occurs on the first time I start my app after downloading from the store.
Question: Is there someone with same issues?
Question: Is there a tool or something which I can use to log the device to get some more information?
Thank you

Assuming you are submitting to the Windows Phone App Store and the OS on the phone running the app is greater than v7.0.7355., you should be able to retrieve the crash dump data from the Windows Phone Dev Centre.
This will only cover crashes within an application and not the underlying OS code.
For more information see: Crash count reports

Check you don't have any code in the debug-only section of the App.xaml.cs
e.g. if your init code sits inside a block starting if ( Debugger.IsAttached )

Related

UWP app crashes with STOWED_EXCEPTION shown in dev store

my UWP runs fine on my PC, I downloaded it from store to check it on my pc and it runs fine, but it is crashing on certain other PCs for unknown reasons, it crashed on the splash screen and dev center is showing me following crash reports.
Please let me know how can I fix or handle these exceptions.
NOTE
"Fluenttt" is the namespace of my app project.
Also note that dev center has no data in log for these exceptions. or no stacktrace shown.
ARM can't be the reason of your crash. ARM package is for mobile device and if you don't upload it when you publish your app, your app won't be available to customer on mobile device in Store.
Without your app, it's hard to tell the reason just according to your failure name. But you could add an UnhandledException event to notify your app about exceptions encountered by the XAML framework or by Windows Runtime in general that haven't been handled by your app code.
Additionally, you could also use Custom event to log the event or activity in your app and you can review the occurrences for your custom events in the Custom Events section of the Usage report in dashboard.

C# - Windows Forms - Windows Sleep

I have an application build on Visual Studio 2013 with C# and Windows Forms.
This application runs on system tray and every 15 minutes (using a System.Windows.Forms.Timer component) visits a REST website, gets JSON data from it and displays them on the application.
The application is in Beta (i have it installed in a few clients for testing) and i was informed that very rarely, after computer recovers from sleep mode it will throw an exception (you can continue using it pressing the continue in the popup window as i was informed).
I have never seen this error in any of my development rigs (Windows 7 64bit, Windows 8.1 and then updated to Windows 10). The two clients that informed me about this exception were running Windows 7 32bit and 64bit.
I have seen this but what should i do when Mode is changed? Should i stop the Timer and then restart it when the Mode changes back to PowerModes.Resume?
As per the answer to this SO Post, Timer checks if any event has missed and fires accordingly. So the exception might be related to getting data from the REST website.
Maybe the exception occurs because your network card is turned off by the OS to save power. Try getting some details of the exception.

Losing data/files after app closes Xamarin Forms

I am developing a crossplatform app with Xamarin and got stuck with this problem.
Every time I launch my app, all the data I had saved before is lost.
To give more details, I am using SQLite to persist some information and even storing some image files in the app's default directory. When I am running the app, I can persist everything successfully and even retrieve the data that I just persisted. But if I close the app and relaunch it, all the information and the files are gone.
To get the directory, I am using the code below, which is suggested in the Xamarin tutorials.
string documentsPath = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
var path = Path.Combine(documentsPath, sqlite Filename);
At the moment I am focusing my tests on the Android, so I don't know if it happens on the other platforms. I am also using the Trial License, maybe it is some limitation related to it.
I am also using Visual Studio 2013.
Does anyone have an ideia about it?
thanks
If by "launching app" you mean starting new debuggin session from VS just go to Tools - Options - Xamarin - Android Settings and tick "Preserve application data/cache on device between deploys" option.
Xamarin Studio should have same option somewhere.
If you are developing the app on VS and deploying it to a test device the data may not persist as I explain below.
What I discovered is that when I close the app on the phone (at least on the iPhone 12 I am testing with) and then reopen the app by launching it again on the phone, the data persists.
Now, if I then relaunch the app from VS the data still persists. Good.
However, when I make a change to the app I find that I need to eliminate the app on the phone for VS to install the new app. It is annoying, but I have gotten used to deleting the app on the phone before launching it again in VS. In this case the data does not persist. Removing the app on the phone removes its data as well. This all makes perfect sense but it was confusing when I first started testing my app with sqlite.

Application silently terminates at launch Windows Phone 8

I created simple WP8 application with database and I am having problems trying to submit it to store. Application is quite simple it allows to search through database that I attach to application. Everything works fine using all emulators and Lumia 620, but I am unable to successfully submit it to store. When I set my Database.sdf Build action to Embedded Resource I get following certification error:
The application cannot be tested for compliance for Windows Phone Application Certification Requirements because it fails
to launch on all Windows Phone devices. The application silently terminates at launch.
But when I changed Build action to Content application passed certification and was published to store. To make sure that everything works fine I downloaded it and was unable to run it, it closed immediately...
I managed to reproduce this error by opening MyApplication.xap and renaming Database.sdf to something else. So I think problem is with encryption and I should reference database in code differently, but not sure how. Any ideas ?
DbDataContext context = new DbDataContext(#"Data Source = 'appdata:/Database.sdf';");

Running a process from an app started from a Windows 7 service

I got a c# windows service which starts an app using this method: http://www.codeproject.com/Articles/35773/Subverting-Vista-UAC-in-Both-32-and-64-bit-Archite
This app starts another hidden c# console app which just sends a picture to connected printer and terminates.
The problem is that the second app doesn't work in this case.
If the first app started not from the service everything works fine. If the first app started by the service, printing fails with a strange error about not having anough paper or something.
So this means that the printing app is being started somehow differently. Does anyone have a clue what's going on and how to debug it?
Thanks.

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