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windows-8.1 interview questions

Top windows-8.1 frequently asked interview questions

Run Windows 10 Universal Apps on Windows 8.1

Is it possible to run a windows 10 universal app on windows 8.1? I searched a lot, but I didn't find a clear answer on MSDN etc.

Thanks.


Source: (StackOverflow)

Asp.net 4.0 has not been registered

When I try to open my Visual Studio project I get the following error:

Asp.Net has not been registered on the webserver you need to manually configure your webserver for Asp.net 4.0.


Update:
Nevermind I fixed it:

I just repaired .Net Framework 4.0 and the issue was resolved.


Source: (StackOverflow)

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ADB Driver and Windows 8.1

I waste a lot of time trying to successfully install the ADB driver for my tablet in Windows 8.1. So here I will post what I did, in case anyone has the same problem.


Source: (StackOverflow)

Windows 8.1 / Windows 10 breaks my ASP.NET / IIS : "Service unavailable"

With Windows 8.1 finally released to MSDN/Technet today I came across the following issue running my ASP.NET application after doing an in place upgrade with Win 8.1 RTM:

Service Unavailable

HTTP Error 503. The service is unavailable.

  • The AppPool has died and shows a status of Stopped
  • The IIS log has nothing
  • There's a clue is in the Windows Application log which contains this error

    The Module DLL C:\WINDOWS\system32\inetsrv\rewrite.dll failed to load. The data is the error.

How can I recover my IIS to make it work again?


Source: (StackOverflow)

Windows store app deployment error

I just downloaded and installed Visual studio on my computer (windows 8.1) to start building windows 8 apps. The problem is when I try to run any application this error message shows up (the application from this error message is called Parcels.comStarter):

Error 1 Error : DEP0700 : Registration of the app failed. Deployment Register operation on Package a783768f-d79c-495b-bf64-e59e4297fb42_1.0.0.0_neutral__1mfyfctfxa0tr from: (d:\Gebruikers\wardv_000\Downloads\Parcels.comStarter\Parcels.comStarter\Parcels.com\bin\Debug\AppX\AppxManifest.xml) failed with error 0x8E5E0530. See http://go.microsoft.com/fwlink/?LinkId=235160 for help diagnosing app deployment issues. (0x80073cf9) Parcels.com

I searched the entire internet but I didn't found a solution. I also did reinstall visual studio and I still have the problem.

Thanks in advance


Source: (StackOverflow)

How to stop credential caching on Windows.Web.Http.HttpClient?

I am having an issue where an app tries to access resources from the same server using different authentication methods, the two methods are:

  • Credentials (NTLM, Basic, etc)
  • OAuth (Bearer)

Setup HttpBaseProtocolFilter

The HttpBaseProtocolFilter is setup to:

  • disable Caching
  • disable automatic UI credential request popup

Code

HttpBaseProtocolFilter filter = new HttpBaseProtocolFilter();
filter.CacheControl.WriteBehavior = HttpCacheWriteBehavior.NoCache;
filter.CacheControl.ReadBehavior = HttpCacheReadBehavior.MostRecent;
filter.AllowUI = false;

Adding Server Credential

If the resource needs credentials then I use:

filter.ServerCredential = new PasswordCredential(
                RequestUri.ToString(),
                UserName,
                Password);

HttpClient httpClient = new HttpClient(filter);

Adding OAuth Token

If the resource needs a Bearer token I use:

HttpClient httpClient = new HttpClient(filter);
httpClient.DefaultRequestHeaders.Authorization = new HttpCredentialsHeaderValue("Bearer", token);

The ServerCredential are null

filter.ServerCredential = null

Getting response from server

using(httpClient)
{
   using(HttpRequestMessage requestMessage = new HttpRequestMessage(new HttpMethod(method), RequestUri))
   {
       using(HttpResponseMessage response = await httpClient.SendRequestAsync(requestMessage))
       {
           // Do something with response
       }
   }
}

The issue

If the HttpClient request returns a 200 (OK) using ServerCredential, then every following Bearer request also returns 200 (OK) even if the Bearer token is invalid and filter.ServerCredential is null.

It looks as if the filter.ServerCredential is cached and all subsequent calls are authenticated with the cached credentials.

I have to restart the app if I want to do a Bearer authentication.

How can I remove, disable or clear the ServerCredential of the Windows.Web.Http.HttpClient?


Things I've tried:

Deleting all cookies

var cookieManager = filter.CookieManager;
HttpCookieCollection myCookieJar = cookieManager.GetCookies(RequestUri);
foreach (HttpCookie cookie in myCookieJar)
{
    cookieManager.DeleteCookie(cookie);
}

The myCookieJar is empty.

Something with PasswordCredentialPropertyStore

Windows.Security.Credentials.PasswordCredentialPropertyStore credentialPropertyStore = new Windows.Security.Credentials.PasswordCredentialPropertyStore();

The credentialPropertyStore is empty.

AND

PasswordCredentialPropertyStore's method Clear is reserved for internal use and is not intended to be used in your code.

Any ideas?


Source: (StackOverflow)

Unable to activate windows store app the app didn't start

First of all I would like to say that I already tried all the solutions I could find on the internet, including Unable to Activate Windows Store App

I recently upgraded my Windows 7 machine to Windows 8.1 to be capable of developing Windows Store apps using Visual Studio 2013. When I open a blank project (Windows Store -> Blank App) and run it I get this error:

Unable to activate Windows Store app 'Package Name'. The App1.exe process started, but the activation request failed with error 'The app didn't start'.

See help for advice on troubleshooting the issue.

I already tried:

  • Reinstalling Windows (Clean install)
  • Reinstalling Visual Studio 2013
  • Installing Visual Studio 2012 (same error)
  • Deleting "bin" and "obj" folder
  • Cleaning the solution
  • Uninstalling the app from start menu
  • Creating a new project
  • Acquiring the license multiple times (the license is valid)
  • Making sure that app.config doesn't exist
  • Investigating the Windows Event Log which says

Activation of the app 'Package Name' for the Windows.Launch contract failed with error: The app didn't start..

but found nothing useful

  • Adding a new Windows user
  • Run everything as administrator
  • and at last, changing the desktop background :)

None of this did bring a solution. Does anyone have an idea what else could be the reason for this error?

Thank you.


Source: (StackOverflow)

__doPostBack is undefined in IE11

Using a readymade asp HyperLink control, IE 11 is giving the error SCRIPT5009: __doPostBack is undefined with a link to here: http://msdn.microsoft.com/en-us/library/ie/xyf5fs0y(v=vs.94).aspx

This is seen in the F12 devtools console window.

Has anybody encountered this yet and is there a fix? This is a production environment.

EDIT: Applying hotfix http://support.microsoft.com/kb/2600088 didn't work for me, and IE 10 on Windows 8 works fine.

There is more recent article from Scott Hanselman with updated information. http://www.hanselman.com/blog/IE10AndIE11AndWindows81AndDoPostBack.aspx I will attempt these fixes and update this question but this appears to be isolated to windows 8.1 and IE11.


Source: (StackOverflow)

MediaElement web Video doesn't stop buffering

I m using MediaElement to play a web video. When I left the page I noticed in the Task Manager that my app was still using 10% of network and didn't drop till it finished downloading video.

I tried doing the following but no luck.

    //open link;
    mediaElement.Source = welcomeVideoURL;

    //when I leave the page OnNavigatedFrom()
    mediaElement.Stop();
    mediaElement.ClearValue(MediaElement.SourceProperty);
    mediaElement.Source = null;

Also tried to set the source to a dummy link but still no luck.

I thought that opening the Link as a Stream and use mediaElement.SetSource() could work but I haven't found anything on that...maybe I m not searching correct.

Thank you.


Source: (StackOverflow)

How do you scale the title bar on a DPI aware win application?

I am making my app dpi-aware per monitor by setting <dpiAware>True/PM</dpiAware> in the manifest file. I can verify with process explorer that this is indeed working or by calling GetProcessDpiAwareness.

This is all working fine and I can scale anything in the client area fine in my code. However, my only problem is that if I drag my app from a system-dpi monitor to a non-system dpi monitor, the title bar and any system menu would either become too big or too small. This isn't the case for most built-in apps (e.g. calc, edge browser, etc..) so there must be away to scale it properly. Does anyone how the devs at MS did this?

The screenshot below should explain my problem better. Also notice, that the padding between the close, min, and max button is different when it's scaled (96dpi).

Screenshot

Sample app I'm attaching a very simple app that is per-monitor dpi aware.


Source: (StackOverflow)

Windows Phone 8 Emulator not launching. Error code 0x80131500

I have problem with Visual Studio 2012 (OS: Windows 8.1 Preview)

  1. Create empty project (Windows Phone App)
  2. Press F5 to start debugging.

And I get 0x80131500 error code, with no detailed description. Only this: Deployment of application to device failed.

Output:

1>------ Deploy started: Project: PhoneApp1, Configuration: Debug Any CPU ------
1>Deploying C:\Visual Studio 2012\Projects\PhoneApp1\PhoneApp1\Bin\Debu\PhoneApp2.xap...
1>Connecting to Emulator WVGA 512MB...
1>Deployment of application to device failed.
1>0x80131500

Has anyone encountered such a problem. How it can be solved?


Source: (StackOverflow)

Why is there no Windows Phone version of Visual Studio Express 2013?

I'm planning a side project with some colleagues but not everyone has licenses. We were thinking of releasing an app for both Windows 8/8.1 and Windows Phone 8 platforms. I don't have a lot of experience working with Express versions, but for some reason Visual Studio Express 2013 for Windows Phone seems to not exist on their site, but without any explanation. I'm wondering if anyone knows if Windows Phone development:

  • exists normally in 2013, and the marketing page is simply botched?
  • can not be done at all in Visual Studio Express 2013?
  • can be done in Visual Studio 2013 Express for Windows, after installing a Windows Phone SDK?
  • can be done without an MSDN License only in Visual Studio Express 2012?

Source: (StackOverflow)

Installing USB driver for Nexus 4 (with KitKat) on Windows 8 64-bit - "no compatible software driver"

I'm desperately trying to install ADB USB drivers for my Nexus 4, which (as you might know) are required for any form of Android Development. You could also say, that they are the single most necessary tool used for Android programming, right? I have already often set up an Android Development Environment for my old HTC Desire, but I am failing with setting it up for my Nexus 4.

The way I go about it:

  • Running Windows 8 and 8.1 Preview (tried everything on two different machines)
  • Downloading the Android Development Tools from Google (SDK+ADT+Eclipse+etc.)
  • Downloading the Google USB Drivers (v8) via Android SDK Manager
  • In the Device Manager i have an entry "Nexus 4" which I right-click and then I select "Update Driver Software..."
  • -> Browse my Computer for driver software -> Let me pick a list of device drivers on my computer -> Have Disk... -> Choose Path to Google Drivers -> Dialog occurs:
  • "The folder you specified doesn't contain a compatible software driver for your device. [...]"

I really do not know what the problem is. Some things I already tried include:

  • Doing everything on USB3/USB2 Port
  • Changing Computer Connection Mode to PTP (instead of MTP)
  • Doing everything on Win8/Win8.1 Preview
  • I tried to install the universal ADB Driver: download.clockworkmod.com/test/UniversalAdbDriverSetup6.msi without any significant result

I fear that the problem is because of the new driver version (v8) or KitKat, because I can't find any working solutions on the net and KitKat is relatively new, however, does anyone have a solution to this?


Source: (StackOverflow)

What is [NotifyPropertyChangedInvocator] in C# when implements INotifyPropertyChanged?

I see two types of implementation of INotifyPropertyChanged

  • The first one:

    public abstract class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
    
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
    
  • The second one:

    public abstract class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
    
        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
    

In 2nd one you see there is an extra attribute [NotifyPropertyChangedInvocator] on the method OnPropertyChanged

In my case both behaves same but what, why and when to use this [NotifyPropertyChangedInvocator], what are benefits of this? I've searched on internet but couldn't find any good answer.


Source: (StackOverflow)

doPostback failing in IE 11+ Windows 8.1

I am getting blank page in IE 11 in Windows 8.1 Preview.After Inspecting the page I assumed that following code might be the culprit,since after these line there is not further line displayed debugger window, So code is breaking after this line.

IE 11

<!-- <form name="aspnetForm" method="post" action="Register" id="aspnetForm">
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTkwNDQ3O

I tried the same page in Chrome Version 29.0.1547.57 m in Windows 8.1 Preview It is working fine there and I get following code.

CHROME

<script type="text/javascript">
//<![CDATA[
var theForm = document.forms['aspnetForm'];
if (!theForm) {
theForm = document.aspnetForm;
}
function __doPostBack(eventTarget, eventArgument) {
if (!theForm.onsubmit || (theForm.onsubmit() != false)) {
    theForm.__EVENTTARGET.value = eventTarget;
    theForm.__EVENTARGUMENT.value = eventArgument;
    theForm.submit();
}
}
//]]>
</script>

-->


Source: (StackOverflow)