Windows Phone 7: free tools, captive Marketplace

Mix10 Microsoft aims to lure Windows Phone 7 developers with free tools. That's the good news. The less-good news is that Redmond plans to lock down the platform à la Apple's App Store.

These revelations were part of Microsoft's baptism of the development platform for Windows Phone 7 on Monday at the Mix10 conference for web designers and developers in Las Vegas, Nevada.

When building apps for Windows Phone 7, developers can choose between Silverlight, intended for general applications, or XNA, a .NET game development framework.

The three tools Redmond is offering are Visual Studio 2010, including a free Express version as well as an add-in for the full IDE, Expression Blend 4.0 for designers, and XNA Game Studio 4.0. Testing and debugging can be performed via an emulator - a virtual machine running the same operating system as a real device - or on a connected device.

Microsoft VP Scott Guthrie announced that the Windows Phone Editions of all three tools will be free, both in their preview versions and after the full release. The technical preview version is now available here.

Microsoft will support the platform with a location service that enables applications to reference the user's location - subject to the user's consent - and a notification service that lets applications receive notifications from the cloud, thus avoiding the need to poll for events.

The Windows Phone 7 hardware platform is tightly standardised, so developers can count on features such as hardware acceleration, an accelerometer, and a multi-touch user interface. The game platform is linked to XBox Live. During the keynote at Mix10, Microsoft's demos included Netflix video streaming and Foursquare location-based social networking.

Windows Phone 7 will be an immediately familiar platform for existing C# and Silverlight developers. The user interface appears compelling, and Silverlight features such as Deep Zoom, which lets you zoom into fine details on large images, are well-suited to a mobile device.

Less attractive is that Microsoft appears to be copying Apple's App Store approach, requiring all applications to go through a certification process and be sold only through Microsoft's Windows Phone Marketplace. This lock-down is explained in developer documentation, which says:

A set of tools will help the developer to submit and certify their applications for the Windows Phone Marketplace. Applications are submitted in a .XAP file format, which is essentially one compressed file that contains all the files that are needed by the application. Developers can track their submission status and then receive a notification once the certification is complete. After an application is certified, it can then be submitted for publishing on the Windows Phone Marketplace. Developers can set pricing and select the markets in which they wish to publish the application.

Application updates can go through the certification and publishing process again in order to fix bugs, add new functionality, or provide whole new versions.

The Windows Phone Marketplace provides the one place where developers can make their applications available for purchase by consumers.

Another troubling issue is that Microsoft said nothing at Mix10 about native-code development. Many mobile developers use C or C++ for their efficiency and performance, and have existing libraries in those languages. There have been hints that native-code deployment will be possible subject to special consent from Microsoft, but whether that will be possible for general development is not yet clear.

In addition, as The Reg reported last month, the Windows Phone 7 series is a new platform, and existing Windows Mobile applications will not run on it.

Microsoft has also announced the release candidate for Silverlight 4, and updated tools for general Silverlight development. These are available here. ®