Universal apps are the applications that are built using the Universal Windows Platform (UWP). This Windows app development platform is introduced by Windows 10 to eliminate the barriers of OS, input modalities and different form factors of various devices for an app to run. Previously, the apps that were built for Windows 8 platform were supported only by the Windows 8 and Windows 8 phone devices. But the basic idea with Windows 10 app development was to create universal apps that can run on variety of devices irrespective of their input modalities, screen resolutions, DPI density and other features they support. The apps are no longer created to target a specific operating system but for the universal device family. One benefit of creating apps for these device families is that these can run on any, all or variety of devices like phones, tablets, desktops, Xbox, surface hubs etc.

Special Features of Universal Windows Apps Development on Windows 10

• Developing apps for target device families not for a single OS.
• Apps are distributed in a single package and therefore they can deployed and updated seamlessly.
• It is possible to submit and manage apps for Windows devices in one place.
• The core APIs of UWP are similar for all Windows based device families. Hence, apps developed on UWP can run on any Windows 10 device.
• Windows provides lot of resources to make your apps engaging like live tiles, push notifications, The Action Center, background execution, triggers and support for voice and Bluetooth devices.
• It is possible to optimize the user interface of your app with universal controls and panel facilities offered by Windows.
• Special tools and adaptive scaling feature enables you to design your app’s UI to match various screen resolutions and DPI differences across devices.
• Windows universal apps can receive inputs through various devices like pen, mouse, keyboard, controller or a simple touch.

One of the best things about universal Windows apps is that they can be developed with programming languages that are familiar with the developers like C# or VB with XAML, JS with HTML or .NET. You can use the .NET technology to build UWP apps that can run on almost any kind of device. For this purpose, you will initially require installing the UWP tools that will come with installation of Visual Studio 2015. If you have VS already then initially install and run the Windows Tools Installer. Then go to Control panel > Programs and Features > Visual Studio 2015. Then click on change. In set up, click modify and select Tools for Windows Apps. This will install the .tools required for developing universal windows apps with .NET.

The important things that are part of .NET UWP Windows apps development are as follows:

1. Adaptive XAML using which designers can design adaptive user interfaces that can scale to any device.
2. You need to write adaptive code in .NET by calling platform-specific Windows Runtime APIs.
3. The .NET core framework or CoreFX for easy code development. Use only the latest version of .NET core which supports the most desired features like System.Net.Sockets, HttpClient, WCF client etc.
4. Build the app in release mode as this will enable .NET native compiler for your app. This compiler converts your code into native machine code which is fast, lean and self-contained. This will speed up your app for faster start up and better overall performance.
5. With .NET Core CLR runtime, you can edit, run and debug your code simultaneously. With Edit and Continue features, it enables faster deployment and rich debugging environment.
6. You should create an Appx package for submission of your app to the Windows Store.

The above highlighted points give you the idea of a few important activities for universal windows 10 apps development. However, internet is full of demonstrations and tutorials to guide you for the process. Hence, referring them will be better idea to go for .NET UWP apps development.