300+ TOP Windows Phone Interview Questions – Answers

1. What Is Windows Phone?

Windows Phone (known as WP) is a proprietary smartphone operating system developed by Microsoft. It is the successor to Windows Mobile, although it is incompatible with the earlier platform. With Windows Phone, Microsoft created a new user interface, featuring a design language named “Modern” (which was formerly known as “Metro”). Unlike its predecessor, it is primarily aimed at the consumer market rather than the enterprise market. It was first launched in October 2010 with Windows Phone 7.

2. What Is Windows Phone User Interface?

Windows Phone features a user interface based on Microsoft’s Windows Phone design system, codenamed Metro, and was inspired by the user interface in the Zune HD. The home screen, called the “Start screen”, is made up of “Live Tiles”, which have been the inspiration for the Windows 8 live tiles. Tiles are links to applications, features, functions and individual items (such as contacts, web pages, applications or media items). Users can add, rearrange, or remove tiles. Tiles are dynamic and update in real time – for example, the tile for an email account would display the number of unread messages or a tile could display a live update of the weather. Since Windows Phone 8, live tiles can also be resized to either a small, medium, or large appearance.

3. What Is Windows Phone Web Browser?

Internet Explorer on Windows Phone allows the user to maintain a list of favorite web pages and tiles linking to web pages on the Start screen. The browser supports up to 6 tabs, which can all load in parallel. Other features include multi-touch gestures, smooth zoom in/out animations, the ability to save pictures that are on web pages, share web pages via email, and support for inline search which allows the user to search for a word or phrase in a web page by typing it. Tabs are synced with Windows 8.1 devices using Internet Explorer 11.

4. What Do You Know About Windows Phone Media Support?

Windows Phone supports WAV, MP3, WMA, AMR, AAC/MP4/M4A/M4B and 3GP/3G2 standards. The video file formats supported on WP include WMV, AVI, MP4/M4V, 3GP/3G2 and MOV (QuickTime) standards. These supported audio and video formats would be dependent on the codecs contained inside them. It has also been previously reported that the DivX and Xvid codecs within the AVI file format are also playable on WP devices.

5. Explain Windows Phone Multitasking?

Multitasking in Windows Phone is invoked through long pressing the “back” arrow, which is present on all Windows Phones. Windows Phone 7 uses a card-based task switcher, whereas later versions of Windows Phone utilize true background multitasking.

6. What Is Windows Phone Bluetooth?

Windows Phone supports the following Bluetooth profiles:

• Advanced Audio Distribution Profile (A2DP 1.2)
• Audio/Video Remote Control Profile (AVRCP 1.3)
• Hands Free Profile (HFP 1.5)
• Headset Profile (HSP 1.1)
• Phone Book Access Profile (PBAP 1.1)
• Bluetooth File Transfer (OBEX) (from Windows Phone 7.8)

Windows Phone BTF support is available from Windows Phone 7.8, but is limited to the transferring of pictures, music and videos via a ‘Bluetooth Share’ app.

7. Explain Windows Phone Hardware?

Windows Phone 7 devices were first produced by Dell, HTC, LG and Samsung. These hardware partners were later joined by Acer, Alcatel, Fujitsu, Toshiba, Nokia, and Chinese OEM ZTE.

Windows Phone 8 devices are currently being produced by HTC, Huawei, Nokia, and Samsung.

At the 2014 Mobile World Congress, Microsoft announced that upcoming Windows Phone 8.1 devices will be manufactured by Gionee, HTC, Huawei, JSR, Karbonn, LG, Lenovo, Longcheer, Micromax, Nokia, Samsung, Xolo, and ZTE. Sony (under the Xperia or Vaio brand) has also stated its intention to produce Windows Phone devices in the near future.

8. Can We Control The Web Browser Controls Zoom?

No. There is no programmatic way to zoom the control. You should include a viewport meta tag to set the initial scale level.

9. How To Restart Or Shutdown My Application Programmatically?

There is no API to do this. Hitting ‘back’ when there is only one page left on the stack is the way to exit the application. Hitting Start button does not exit, just pauses it.

10. How To Detect If My Application Is Exiting So I Can Save State?

You can listen to Application.Exit, but this might be too late most of the time. You should listen for the Pause event and save your state there.

11. How To Pin An App On The Emulator?

You simply run the application once to deploy it, and then browse to the application list, and click and hold the application icon, you will then get a context menu with the option to pin.

12. Tell Me Will Texttrimming Property Be Available On Textblock?

No. You have to hack it up with your own measure.

13. Suppose I Am Hitting System.invalidoperationexception In The Navigate Method Of The Webbrowsercontrol. What Gives?

Don’t call the navigate method from your PhoneApplication Page’s constructor. you should wait until control is loaded before you Navigate.

14. Explain I Am Getting Too Many Mouse Leaves On My Custom Control.?

As far as the emulator is concerned, there is no mouse; everything comes in as a touch event and when the “finger” comes up, the mouse has left the scene, since there’s no reasonable location for it to be at.

15. Tell Me Is It Temporary That The Control Styles Are Included In App.xaml?

Yes. In the final product a master ‘generic.xaml’ will be injected into your application. This injected dictionary will be based on the theme selected when your app is started. Dictionary is injected every time your app starts.

16. I See Applications Using Listbox That Show Scrollbar Only On While Scrolling. How Can I Detect That I Am Scrolling?

Microsoft hopes the templates in a future build will have this Scrolling and NotScrolling VisualStates.

17. How To Dismiss The Sip Programmatically?

Set the Focus() to some other UIElement that is focusable.

18. How To Detect The Resolution Of My Device?

(App.Current.RootVisual as FrameworkElement).ActualHeight and (App.Current.RootVisual as FrameworkElement).ActualWidth gives you device’s resolution.

If you want to know the visible size (taking AppBar / SystemTray into account) then just ask for it off the page instead.

19. Can Not Find Phoneapplicationpage.fullscreen In April Ctp?

SystemTray is an attachable property now. You can use it in your page xaml, something like:

xmlns:shell=”clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone.Controls.Navigation”
shell:SystemTray.IsVisible=”true”>

20. How To Save Silverlight Ui Elements Into An Image?

In a later preview, before RTT, WriteableBitmap will have a method to save as JPEG

21. How To Save Screen From An Xna App?

Texture2D has a SaveAsJpeg method and a SaveAsPng method. Be aware that Zune does not sync pngs, so saveasjpeg is recommended

In April’s CTP, you could try:

MediaLibrary library = new MediaLibrary(); library.SavePicture(“My Picture”, streamToJpegData); // You can use this from inside a Silverlight app provided you have the ID_CAP_MEDIALIB capability. // You do have to make sure the Stream you pass in contains JPEG file data, but otherwise it should work for you.

22. What Are The Supported Codecs For Video?

Supported Codecs and container formats are listed in MSDN documentation: http://msdn.microsoft.com/en-us/library/ff462087(VS.92).aspx Note: The Device Emulator does not have hardware decoders so the codec support on the device emulator is much less than what is listed. For Emulator you only have WMA, WMV, and VC1 software decoders.

23. What Is Send To Ap And Who Gets It?

Send to AP is the Associated Press’ way of extending the journalism floor to its users. Users can send in news tips and photos directly to AP editors via the Send to AP option under Settings. User information is solely used for the purpose of contacting the user to verify the tip or to gather more information.

24. How To Change Language Settings?

1. Go to the Settings button on your device
2. Select General
3. Select International
4. Choose the desired language

25. Can I Get Weather For My Location?

Windows Phone 7 supports international locations, which a user can search for by inputting the city name.

26. How To Edit Location For Weather?

Users can customize Weather under Settings. Locations for Local News and Weather are handled separately. Windows Phone 7 supports international locations.

27. How To Edit Locations For Local?

Users can customize Local under Settings.

28. How To Send Suggestions On How To Better The App To The Ap?

Users can send feature requests and feedback to the AP via the Feature Request option in the application. Users can find the feedback options under Settings.

29. What Content Can I Share/save?

• Users can share content with their friends via the share feature available on every story and photo.
• Users can save articles, photos and videos to the Saved folder in AP Mobile. The saved folder is on the fourth panel of the first screen

30. What Is The Windows Phone Front Page?

Users can add and order as many categories as they want and two headlines for each category will be displayed on the Front Page.

31. How To Customize Front Page?

Users can find the Customize option under Settings on the first screen.

32. Some Images Look Different When Synced To The Device And Read Programmatically. Do Decoders Change These?

No. decoders and apps show them as they are. Zune software does resize them when syncing them, that might be the cause for your differences

33. How The Volume Work Between Apps And Hardware Buttons On The Device?

Applications get to control the volume for their streams but the hardkeys control the final master output level.

34. Where Is Httputility Class, Since There Is No System.windows.browser Namespace?

HttpUtility is in System.Net namespace You can also find alternatives for escaping strings at Uri.EscapeDataString and Uri.unescapeDataString ..

35. Suppose My Site Is Down, And Async Calls Are Taking Too Long To Timeout. How Can I Set A Reasonable Timeout?

Per MSDN docs, you should call Abort() on your request when you feel iti s appropriate timeout

36. Tell Me Are There Apis To Read Rss/atom Feeds?

You could use System.ServiceModel.Syndication from the desktop since it dependencies are entirely present in CF

37. How To Sniff Network Traffic From The Emulator?

Netmon 3.4 (beta) defintitely works. Fiddler works too. If using fiddler, remember to switch it to either trap “non-browser” or “all” traffic and start fiddler before launching the emulator.

38. Tell Me Is Wcf Supported In Windows Phone?

WCF is supported on WP7.

When you look at the SL3 version of WCF, WP7 supports that except for the following:

• PollingDuplex support
• Runtime code generation support for ChannelFactory.CreateChannel APIs
• Astoria/Azure support

39. Explain Does The Web Browser Control Share The Ie Cache?

No. Each app has its own wininet cache. The webbrowser control instances in your app will use that app’s cache. The IE cache will be separate

40. Tell Me Is There A Way To Detect If Application Is Idle?

No. You have to do that yourself. yourself (you could subscribe to ManipulationStarted on the root frame with handled=true and then use a simple timer).

41. Explain Where Is Xmldocument Class?

Instead of Xml Document, using XDocument from System.Xml.Linq.dll

42. Suppose I Am Trying To Receive Toast Notifications In Emulator App. I Got Everything Setup But Notification Does Not Show Up In Emulator At All?

Make sure you have a product / publisher name set in the manifest.

Open WindowsPhonepmanifest.xml, under Properties. Edit Publisher=”” to Publisher=”something”. Redeploy.

43. How To Access The Liveid Credentials A User Has Entered Into The Device?

In this release, the credentials are not available to third party apps. You will need to prompt the user for credentials and manage these within your app.

44. Tell Me Is Securestring Supported In Windows Phone?

No. Securestring is not in Silverlight.

45. How To Deserialize Json From A Rest Call?

Use DataContractJsonSerializer. it is in System.Servicemodel.Web

46. What Happens To Isolatedstorage When App Is Uninstalled?

It gets deleted. Content saved to media library is not deleted on Uninstall

47. Tell Me Where Is The Best Recommended Place To Store Both Static And User-specified Configuration Information?

You can use the IsolatedStorageSettings.ApplicationSettings.

48. Tell Me Is There An Api For Retrieving Information On The Files Located In The Store? I Am Looking To Check When It Was Last Written?

Try IsolatedStorage.GetLastWriteTime

49. Tell Me In My Code The Method Marked By [ondeserialized] Is Never Called After Deserialization. Is This A Known Issue?

The following conditions should be met for a valid OnDeserialized callback:

•  The accessibility of the method should be public. It can also be internal with InternalsVisibleTo provided to the System.Runtime.Serialization assembly.
•  Return type should be void.
•  There should be exactly one parameter which should be of the type StreamingContext.
•  There should be only one of the four callbacks provided on the method.

50. Can You Please Explain The Best Way To Detect That I Am In Design-mode In Expression Blend Or Visual Studio?

DesignerProperties.IsIndesignTool

51. Tell Me Is There A Way To Know If My Code Is Running On Emulator Or Device?

Check System.Environment.DeviceType

52. Suppose I Have Lost One Of The Application Templates In Visual Studio 2010. It’s Available In The File System But Not In Visual Studio. Any Idea?

Try running Devenv /setup.

Running devenv /installvstemplate might also work; but that is going to slow down overall VS performance. The /installvstemplate is a development only option that makes it easy for developer to test their templates. This shouldn’t be used on end user machines. Devenv /setup does a lot of more processing and caching to speed up VS performance.

53. Suppose Have A Very Simple Application That Uses The Applicationbar. The App Bar Shows One Menu Item When In Portrait. However As The Second Image Shows The App Bar Displays Now Items In Landscape Mode. Is That By Design Or A Bug?

Yes, it’s a known problem in the emulator on machines that don’t support the hardware accelerated graphics in the emulator. It works properly on devices and machines that do

54. Suppose I Am Trying To Detect If An External Headset Is Attached To The Phone,can I Use Microsoft.xna.framework.audio.microphone.isheadset?

No. this property is true all the time for the phone