To get started with UWP app development, you must first enable app development for your Windows 10 device. If you are familiar with app development on Windows 8.X, you will recall the need to possess a developer license that had to be periodically renewed with Microsoft. That is no longer the case for UWP apps—once you have enabled development support, you are good to go. Let's look at how to do that.

One of Microsoft's goals for UWP apps is to truly make them universal so that they run on any system based on the core Windows 10 technology—not only traditional desktop computers, but devices ranging from Raspberry Pi, to Xbox One, to Microsoft's new HoloLens.

In this recipe, we will begin by creating a brand new UWP app to see how the process differs from Windows 8.X app creation, and the new capabilities made available to us.

We saw in the previous recipe that creating a new UWP app is pretty simple, but in VS2015, the choices are limited to some basic types. Rather than provide some pre-made templates around common design themes (such as Hub, Split, Items, and so on) as was done previously in VS2013, Microsoft has instead decided to provide us with a blank canvas with which to work. Let's see how we can spruce it up a bit.

The design behind the UWP architecture has been established so that your app can easily be deployed to any device that runs Windows 10. There may be some minor customizations needed depending on the capabilities that various platforms offer, but UWP will not limit you unnecessarily. As a reader of this book though, you are probably developing your UWP on a traditional computer that most likely has a keyboard and a mouse. While this is great for development (and usually, a keyboard is a needed component), this means that your workstation doesn't always match what is available to your app's users. Enter the Windows 10 simulator.

The Windows 10 simulator, available under VS2015, provides the ability to run your UWP app in your choice of Debug or Release builds, so that you can see how it runs and appears on a machine outside of your regular development machine configuration.

This recipe will show how to use the simulator to assist in developing your own...

Windows 10 provides UWP apps the ability to communicate with any other app on the computer, without prior knowledge of what those apps might be, through a concept called contracts. A contract is an operating system level interface that is implemented by consumers or providers of information. The operating system then keeps track of which apps support which contracts, and coordinates the information between apps using those contracts.

Windows 10, as part of its focus on maintaining a trust level in the apps it runs, expects UWP apps to communicate the capabilities they need. A capability is a permission or access right that a UWP app requires for it to run correctly, for example, an app that requires Internet access or local network permissions. There is a range of capabilities that the operating system can provide to UWP apps. An app that doesn't request capabilities from the operating system will be provided minimum level access, which means that...

Given the wide variety of devices that your UWP app can run on, it is important to track performance to ensure you are not being wasteful. Users appreciate improved battery life, and a responsive app is always appreciated by users. VS2015 has several app performance and diagnostic tools available that can help you measure and review its performance to ensure it is as efficient as needed.

The Diagnostic Tools menu provides the following tools: