Application Controls - Metro Revealed: Building Windows 8 Apps with HTML5 and JavaScript - page 58

Figure 3-5. Displaying external content

For the Visual Studio beta, the Internet (Client) capability is checked by default, but you
may also require the Private Networks (Client & Server) capability, depending on where your
content is coming from. Check the capabilities you require and save the manifest. We'll return
to the manifest in Chapter 4 to configure some of the other settings.

■ This is an area that I expect to change before the final Windows 8 release. The
idea of private and public networks is expressed in the Metro manifest capabilities, but not in
the operating system when the user sets up network connections. For the Consumer Preview at
least, all network connections are treated the same way, so the capabilities for a Metro app and
the network model for the operating system will have to converge at some point.

Caution

Summary
In this chapter, I introduced three important structural features for a Metro app: AppBars,
flyouts, and the navigation model. These facilities start to bridge the gap between a generic web
app and the tools for decomposing your application into manageable chunks.
You don't have to use AppBars and flyouts, but your application won't fit into the Metro
model if you don't. Part of the attraction of Metro is to be able to use your HTML5 and JavaScript
skills to create Windows applications. Creating an app that doesn't follow the Metro conven-
tions is to miss the opportunity that Windows 8 presents to the web programmer.
Equally, you could elect to build your Metro app using a single HTML document. But, once
again, this would be a missed opportunity. The constraints that drive web apps toward content
consolidation don't exist for Metro apps, which means that the ease of development, testing,
and maintenance that come from decomposing your content and code are worth exploring. The
HTMLControl and pages features are key enablers to this development style.