Skip to main content

Get current position in Metro app on Windows 8 freeze

Ati incercat pana acuma sa obtineti locatia GPS curenta intr-o aplicatie Metro pentru Windows 8?
Daca nu, trebuie sa stiti ca nu e deloc complicat, este chiar la mintea cocosului API-ul.
Geoposition currentPosition = await new Geolocator().GetGeopositionAsync();
Toate informatiile necesare o sa le puteti gasi intr-un obiect de tip Geoposition. Intr-o aplicatie simpla totul o sa mearga fara nici o problema. Apoi o sa ajungeti sa creati un provider de genul GPSProvider. Fiind o metoda asincrona, aceasta metoda o sa fie apelata cu await, iar codul vostru o sa arate in felul urmator:
public class GPSProvider
    public async Task<Geoposition> GetCurrentPositionAsync()
    // some code.
    return async _geoLocator.GetPositionAsync();
In unele cazuri, cand o sa rulati codul pe un alt thread decat cel principal o sa va treziti ca locatia GPS nu poate sa fie rezolvata, codul ingheata la metoda GetPositionAsync(). Cauza pentru care se intampla acest lucru este ca codul nu ruleaza intr-un mediu MTA (Multi Threaded Apartment) si nu intr-un mediu STA (Single Threaded Apartment).
Aceasta problema apare doar la primul apel, dupa acest apel, metoda poate sa fie apelata din orice locatie fara nici o problema. In specificatiile la acesta metoda se precizeaza ca aceasta trebuie sa fie apelata prima data dintr-un mediu STA, iar apoi o sa functioneze si dintr-un mediu MTA. In spate aceasta metoda apeleaza la randul ei un COM, din aceasta cauza apare aceasta restrictie.
From MSDN:
In apps that use C# or C++ in Windows 8 Consumer Preview, the first use of the Geolocator object to call GetGeopositionAsync should be on the STA thread. Calls from an MTA thread may result in undefined behavior.

Comportamentul este destul de ciudat si neasteptat. Solutia la aceasta problema este sa mutati codul care face apel la metoda GetPositionAsync in xaml.cs sau in orice loc care sa va asigure ca sunteti intr-un mediu STA. O alta solutie este sa va definiti o metoda de warm up, care este apelata din App.xaml.cs de exemplu.


  1. I like the valuable info you provide in your articles. I will bookmark your blog and check again
    here frequently. I'm quite certain I'll learn many new stuff right here! Best of luck for the next!
    My page: restore contacts Microsoft exchange server


Post a Comment

Popular posts from this blog

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

Fundamental Books of a Software Engineer (version 2018)

More then six years ago I wrote a blog post about fundamental books that any software engineer (developer) should read. Now it is an excellent time to update this list with new entries.

There are 5 different categories of books, that represent the recommended path. For example, you start with Coding books, after that, you read books about Programming, Design and so on.
There are some books about C++ that I recommend not because you shall know C++, only because the concepts that you can learn from it.


Writing solid codeCode completeProgramming Pearls, more programming pearls(recommended)[NEW] Introduction to Algorithms


Refactoring (M. Fowler)Pragmatic ProgrammerClean code[NEW] Software Engineering: A Practitioner's Approach[NEW] The Mythical Man-Month[NEW] The Art of Computer Programming


Applying UML and Patterns (GRASP patterns)C++ coding standards (Sutter, Alexandrescu)The C++ programming language (Stroustrup, Part IV)Object-oriented programming (Peter Coad)P…