Building Microsoft ASP.NET Applications for Mobile Devices, Second Edition [Electronic resources] نسخه متنی

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Building Microsoft ASP.NET Applications for Mobile Devices, Second Edition [Electronic resources] - نسخه متنی

Andy Wigley; Peter Roxburgh

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Chapter 1: Introducing Microsoft ASP.NET for the Mobile Web


Consider this scenario: Caroline, software engineer extraordinaire at A. Datum Corporation, is in trouble. After a few high-profile successes, she earns recognition as a key employee. Her technical director becomes interested in wireless Internet devices and asks her to build a mobile Web site that allows field personnel to access their company data remotely. Figure 1-1 illustrates the challenge Caroline faces.

Figure 1-1: Designers of mobile applications face a bewildering number of choices.

After some initial research, Caroline decides Wireless Application Protocol (WAP) is the best approach. Handsets are available, and industry support looks solid. Then the first headache appears: Caroline has to learn a new markup language. She knows Hypertext Markup Language (HTML), but she finds WAP's Wireless Markup Language (WML) so different that she discards her first few efforts until she succeeds in working out how the "cards and decks" structure of a WML page works and figures out how to present meaningful content in such a small display area. Although she wasn't nave enough to assume that an existing HTML Web site would transfer wholesale to a small device, she's surprised by the difficulty she has creating a workable application given the device's small display and limited text-input capabilities. Eventually the application takes shape, written using Microsoft Active Server Pages (ASP)—meaning that Caroline had to refresh her knowledge of Microsoft Visual Basic Scripting Edition (VBScript) and write all the code required to output the appropriate WML markup for her Web pages.

Soon the prototype is ready for beta testing, and Caroline is quite pleased with it. However, the testers report that the application is confusing and unintuitive, which surprises Caroline, who carefully considered its usability. After investigation, Caroline, who had used an emulation of a Nokia phone for testing, learns that her users were working with Openwave browsers. Although both devices conform to WML 1.1 specifications, the WML markup that offers the best usability on each browser differs slightly.

Caroline encounters even more problems. Field personnel at A. Datum Corporation's other main location don't have a network operator providing WAP handsets in their metropolitan area. However, their network operator does offer a mobile Internet service called M-mode service, which uses a different markup language, compact HTML (cHTML). In addition, some of the prototype testers, despite seeing the potential of the service, have recently acquired new two-way pagers, which offer text mobile Internet service—and now they want to access the company data through the service their new pagers offer. Furthermore, the field service managers recently received personal organizers with HTML browsers operating over wireless modems, and they don't want to carry a WAP device as well. The technical director, looking a little disappointed, thanks Caroline for her efforts and walks away scribbling on her indispensable personal digital assistant (PDA), which is—of course—equipped with wireless Internet access, but not for WML.

At this point, Caroline quits the business in disgust and pursues her longtime ambition of guiding outdoor expeditions. Once in the mountains, she finds with some relief that there are no computers in sight and that she can't get mobile data coverage because of the surrounding peaks. Sometimes, however, lying in her sleeping bag, she misses the excitement of software development and thinks back on the mobile project she led at A. Datum Corporation. She realizes that the project would have succeeded if she'd had the following capabilities:

A way to write one application that, when run, automatically generates the correct markup for all major mobile browsers

A runtime smart enough to send not only valid markup, but also markup that actually yields optimum usability on a particular manufacturer's browser

A presentation optimized for each type of browser—so that if, for example, the browser supports color, the browser will use color as appropriate

The ability to lay out the user interface in a graphical user interface (GUI) editor

The ability to code in a proper object-oriented manner so that it's possible to cleanly isolate user interface elements from application logic

Application logic that can be coded in a major language such as Microsoft Visual Basic .NET, C++, C#, or even COBOL, with full access to data and the facilities of the underlying operating system

The ability to customize the user interface for any specific device

An extensible system that easily supports the next generation of mobile devices on the market as well as their applications

These are features that ASP.NET Mobile Controls offer to overcome the obstacles to a successful implementation that Caroline faced.

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