Microsoft’s Build Conference kicked off this morning with keynote addresses focused on Windows desktops, Windows Phone and Windows Surface. These three platforms have been unified from a development perspective, however, as Microsoft announced Windows Universal Apps during the keynote.

“With the Windows Phone 8.1 release, we brought the new Windows Runtime to phones. Now you can produce common apps across phones, PCs and tablets,” said David Treadwell, corporate vice president at Microsoft. “To enable universal Windows apps, we’ve streamlined every phase of the windows development.

“You need to reach customers across multiple devices. Windows will help you do that. We know you’ve made a huge investment in your code and you need to carry that forward. Windows will help you do that. You need to be able to deliver apps across platforms. Windows will do that.”

Kevin Gallo, group program manager at Microsoft, showed off the mechanisms of universal Windows apps with a Visual Studio demonstration. The same code, whether C#, C/C++ or even now JavaScript, can be pushed into any of Microsoft’s three platforms by sharing chunks of code, he said.

“You can very easily mark what code and assets you want to share,” said Gallo. “Since I built this entire thing, I want to share the entire app. It’s taking everything in my Windows 8.1 project—all the code, all the images, and even all my XAML—and moving it into my shared project. Like you, I have some third-party libraries. I used Json.NET here. We don’t assume you’re going to share, but you just move what you want to share and put it in the shared node.”

The results of his work allowed Gallo to quickly transfer a Windows-based full-screen application into a slide-to-browse Windows Phone application.

Treadwell went on to explain that Microsoft Office is being transferred to Windows Phone by becoming a universal Windows app. Kirk Koenigsbauer, corporate vice president at Microsoft Office, demonstrated the advances the Office team has been experimenting with on non-desktop platforms.

“From a developer perspective, the Windows Runtime has been a great place for us to build highly responsive apps,” he said. “We’re trying to bring forward the experiences from Office on Win32 to the modern platform itself.”

Koenigsbauer then demonstrated how the listing of recently used documents linked to Microsoft’s Office 365 online offering, allowing desktops, phones and tablets to see the same recently used list.

Treadwell said that old applications can be ported forward to become universal Windows apps with minimal effort. A demonstration that involved porting old ADO.NET code to a Windows Tablet showed how even synchronous calls could be worked around.

Cloudy lady
Elsewhere at the show, Microsoft demonstrated Cortana, its answer to Apple’s Siri and Google’s Now service. With the release of Windows Phone 8.1, said Treadwell, developers no longer need to define a grammar for interfacing with Cortana. Rather, Cortana can discern needs from its existing cloud-based database.

Cortana is based on the character from the Halo series of games.

Windows Phone 8.1 will also include dozens of new features for developers. New video-editing capabilities will be available. Developers will also have the ability to poll background triggers. These triggers will allow applications to respond to push notifications and geofencing.

Treadwell also announced the open-source availability of Microsoft’s JavaScript interface library, WinJS. The project is now available on GitHub under an Apache 2.0 license. He said the project was also becoming cross-platform.

For those in the Microsoft Developer Network, the Windows 8.1 desktop update is available right now. The rest of the world will be able to update next week.