UWP is one of many ways to create client applications for Windows. For devices that can connect to the internet, UWP apps use WinRT APIs to give them a powerful user interface and advanced asynchronous features.
See Install tools for the Windows App SDK to get the tools you need to start making Windows apps. Then write your first app.
The Universal Windows Platform (UWP) is quickly becoming one of the most popular options for developing cross-platform apps. With UWP developers can write a single app and have it run across all Windows 10 devices – including PCs tablets, smartphones, Xbox, HoloLens, and more.
As UWP continues to gain traction more companies are looking for developers skilled in building UWP apps. This means technical interviewers are posing tough UWP interview questions to thoroughly vet candidates.
To help you ace your next UWP interview and land your dream developer job, I’ve put together the top 25 UWP interview questions with detailed answers. Read on to learn what hiring managers want candidates to know about UWP!
1. What is Universal Windows Platform (UWP)? How does it differ from traditional Windows development?
UWP is Microsoft’s unified platform for building apps that run across all Windows 10 devices. With UWP, developers can use a single API layer and write code once to target phones, PCs, tablets, Xbox, HoloLens, and more.
Traditional Windows development required separate codebases for each device family. UWP eliminates this redundancy by unifying core OS components like the app model, UI framework, and API layer across device families. This unified core makes UWP stand out.
2. What are some key advantages of using UWP for development?
Some major advantages of UWP include:
- Single codebase across devices
- Unified Windows 10 app store
- modern APIs like Composition and XAML
- Robust security model
- Package format utilizing app containers
- Live tiles and push notifications
- Adaptive UI with responsive design capabilities
- Cortana integration and inking support
Overall, UWP empowers developers to build an adaptive, robust app experience on any Windows 10 device.
3. What programming languages can be used to build UWP apps?
The main languages used for UWP development are:
- C# – The preferred language for UWP, used extensively with XAML
- Visual Basic
- C++ with WinRT extensions
- JavaScript and HTML5 via frameworks like Cordova
C# combined with XAML is the predominant choice for UWP developers targeting native app experiences.
4. Explain the UWP app lifecycle.
The four states in a UWP app lifecycle are:
- Not Running: App not launched yet
- Running: App is active and user interacts with it
- Suspended: App is inactive but retains state. It can be terminated if resources are low.
- Terminated: App is shutdown completely. State is lost.
The lifecycle is optimized to preserve battery and resources. Apps are suspended quickly when not active.
5. How is state management handled in UWP apps?
UWP provides suspension state management via the Application class and OnSuspend event. Developers should persist important app data like documents or media state to storage in OnSuspend and restore state in OnLaunched.
For UI state management across suspend/resume, XAML provides SaveViewState / LoadViewState methods to persist tree state.
6. What is a UWP app package? What package types exist?
A UWP app package is a zip archive with the .appx extension containing the app manifest, binaries, assets, dependencies etc. Four types of app package exist:
.appx: Package for a specific architecture.appxbundle: Container for.appxpackages with different architectures.msix: Next-gen package format to replace.appx.msixbundle: Container for.msixpackages with different architectures
7. How are capabilities specified in a UWP app?
Capabilities like camera, microphone, location etc. are declared in the Package.appxmanifest file via the Capabilities node. At runtime, the system checks these capabilities before allowing the app to access the capability. This enforces secure access.
8. What are some key differences between WinRT and UWP?
Some differences between WinRT and UWP:
- Single app package – UWP uses one package across devices. WinRT required separate packages.
- No store association – UWP apps can be sideloaded without store. WinRT required store association.
- Development workflow – UWP uses VS2015+ for unified dev. WinRT used VS 2012/13 with different SDKs.
- Adaptive UI – UWP has adaptive triggers for responsive UI. WinRT had limited support.
- APIs – UWP includes latest APIs like Touch, Timeline, Ink, Composition.
9. How are adaptive UI and responsive design handled in UWP?
UWP provides built-in support for adaptive UI throughAdaptive Triggers, State Triggers, and Visual State Manager.
Adaptive Triggers enable developers to define Responsive Visual States that change UI based on window size changes. State Triggers allow setting visual states based on app conditions. The Visual State Manager applies states at runtime.
These allow creating responsive UIs that adapt across screen sizes and device families.
10. What are some best practices when designing UWP apps?
Some UWP design best practices include:
- Follow Windows UI guidelines and Fluent Design
- Use appropriate navigation patterns – hamburger, tabs, pivots etc.
- Utilize adaptive layout containers like Grid, StackPanel, RelativePanel
- Design for touch, keyboard, mouse and pen input
- Minimize UI crowding with clean layouts
- Offer personalization like theming and UI text size options
- Use appropriate iconography, typography, and color schemes
Following Windows UI guidance results in a polished, intuitive UWP app experience.
11. How are background tasks handled in UWP?
UWP provides background task support via the BackgroundTask class and OnBackgroundActivated event handler. Tasks are registered in the manifest and triggered by the system on events like time triggers, push notifications etc.
Strict constraints exist on background task execution time and resource usage. Tasks must be lightweight and not user-facing. Typical scenarios include periodic data sync, notifications, file transfers etc.
12. What is the MVVM pattern and why is it useful in UWP?
MVVM (Model-View-ViewModel) is a UI architecture pattern that separates UI (View) from business logic (ViewModel). It leverages data binding to connect the two.
MVVM improves testability, maintainability and designer-developer collaboration in UWP apps. The UI layer can evolve separately from the ViewModel logic. The ViewModel can be unit tested without UI dependencies.
13. How does navigation work in a UWP app?
UWP apps typically use XML markup in XAML for in-app navigation. Key frameworks include:
- Frame – For page-based nav between XAML Pages
- NavigationView – For pane-based nav with NavigationPane and Content section
- Pivot – For pivot-based nav across different Views
The Frame allows back stack management while NavigationView provides a nav pane for top-level navigation.
14. How can you reuse UWP app code across platforms like iOS and Android?
Reusable shared app code can be built using C# and .NET libraries that are portable across platforms. Xamarin frameworks like Xamarin.Forms enable sharing UI code using XAML across UWP, iOS and Android.
Business logic and data layers can be packaged as .NET Standard libraries and reused across apps. Azure App Services can also host shared backend app logic.
15. How is app data handled in UWP? What storage options are available?
UWP provides these storage options:
- Local app data – Local folder for data private to the app
- Roaming app data – For data to roam across devices
- Temporary app data – For transient data like caches
- Files and folders – For user files/content using file pickers
- IndexedDB – NoSQL embedded database
- Azure cloud storage – For remote storage on Azure
Temporary and roaming data have size quotas. Azure provides unlimited scale.
16. What is the WinRT API and what does it provide?
WinRT API is the native API for UWP. It provides access to Windows features like:
- UI framework – XAML, Composition
- Media – Graphics, animation, audio/video
- Connectivity – Networking, web services
- Devices – Printing, scanning, location etc.
- Productivity – Cortana, Ink, Pen etc.
- Storage – File access, databases
- Security – Identity, authentication, encryption
WinRT powers UWP’s native capabilities for modern Windows 10 apps.
17. Explain the various application resource access options in UWP.
UWP uses URI schemes to access app resources:
- ms-appx:// – For app package resources
- ms-appdata:// – For app data folders
- ms-resource:// – For compile
Where does UWP fit in the Microsoft development story?
UWP is one way to make apps that work on Windows 10 and Windows 11 devices. It can also be used with apps from other platforms. UWP apps can make use of Win32 APIs and . NET classes (see API Sets for UWP apps, Dlls for UWP apps, and . NET for UWP apps).
The story of Microsoft’s development keeps changing. UWP, along with WinUI, MSIX, and the Windows App SDK, is a powerful tool for making client apps.
There’s one store for all devices
With a unified app store, your app can be used on PCs, tablets, Xbox, HoloLens, Surface Hub, and Internet of Things (IoT) devices. By putting your app in the store, you can make it work on any device or just the ones you pick. You submit and manage all your apps for Windows devices in one place. Do you want to bring your old C desktop app up to date with UWP features and sell it in the Microsoft Store? That’s fine too.
UWP apps integrate with Application Insights for detailed telemetry and analyticsâa crucial tool for understanding your users and improving your apps.
UWP apps can be packaged with MSIX and distributed via the Microsoft Store, or in other ways. Apps can be updated through MSIX no matter how they are shared (see Update non-Store published app packages from your code for more information).
You can choose how youll monetize your app. There are a number of ways to make money with your app. All you need to do is choose the one that works best for you, for example:
- A paid download is the simplest option. Just name the price.
- Trials let people try out your app before they buy it, which makes it easier for people to find and buy than “freemium” options.
- Sale prices to incentivize users.
- In-app purchases.
Intro to UWP (Universal Windows Platform) Apps in C#
FAQ
What is the UWP Universal Windows platform?
Why did Microsoft abandon UWP?
Is UWP still relevant?
What is replacing UWP?
What is the difference between UAP & UWP?
UAP is stands for Universal App Platform and UWP stands for Universal Windows Platform. Both are meant forthe same thing that will enable Windows 10 developers to write one app for ‘All Windows Platform family devices.’ 7. What are the major development differences between WinRT universal app & Windows 10 UWP?
Does Windows 10 have a Universal Windows Platform (UWP)?
Windows 10 introduced the Universal Windows Platform (UWP), which provides a common app platform on every device that runs Windows. The UWP core APIs are the same on all Windows devices. If your app only uses the core APIs, it will run on any Windows device no matter whether you are targeting a desktop PC, Xbox, Mixed-reality headset, and so on.
What is a UWP app?
UWP apps can make use of Win32 APIs and .NET classes (see API Sets for UWP apps, Dlls for UWP apps, and .NET for UWP apps ). The Microsoft development story continues to evolve, and along with initiatives such as WinUI, MSIX, and the Windows App SDK, UWP is a powerful tool for creating client apps.
How do I create a UWP app?
UWP apps use WinRT APIs to provide powerful UI and advanced asynchronous features that are ideal for internet-connected devices. To download the tools you will need to start creating Windows apps, see Install tools for the Windows App SDK, and then write your first app. Where does UWP fit in the Microsoft development story?
