Using Emulators

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Similarly, some devices offer more room for text than others, and so on. You sometimes want to be able to send different sources to different devices or models. You accomplish this by defining device filters, then doing a kind of elaborate, roundabout Select Case or If Then comparison. Why this simple, common computing act of branching has to be made elaborate and unique for mobile computing programming I can't say. My guess is that this new technique probably fits in better with the invisible structures deep within .NET, and it also allows for protocols such as querying devices, asking them to tell you details about their capabilities. You can also deal with multiple devices by setting up a filter system. My only problem with this is that we all know how to use Select Case and If Then, so why set up method testing? It's sure inconvenient for us programmers up on the higher levels where everyday coding goes on.

And, if you're not yet convinced that new technologies often hand us totally unnecessary extra debugging worries, note that in VB.NET variable names, property names, and values are not case-sensitive. We VB.NET programmers are proud that our language doesn't introduce burdens like case-sensitivity into the language. But, alas, when you compare property values in these mobile-project filters (unless they're Boolean where True and true do match), the values are case-sensitive. Here's yet another exception to the traditional rules for you to memorize, or suffer later from confusing bugs in your code.

You can roughly design your mobile application's user interface, and write your code-behind programming to get the kinks worked out, all as described above using Internet Explorer as the target ''device." However, before deploying a mobile application, you'll doubtless want to test it with real PDAs or cell phones. But do you have to buy dozens of cell phones and PDAs? One easy way to test your mobile applications is to use emulators that, via software, mimic the I/O facilities and behaviors of a particular device.

Custom Device Emulators

You can search the Internet for devices and their emulators. Most device manufacturers make emulators available for your use. Microsoft, for example, offers an emulator for the Pocket PC from:

 http://microsoft.com/downloads/details.aspx?FamilyId=9996B314-0364-4623-9EDE- 0B5FBB133652&displaylang=en

The entire download is an SDK with which you can create and test applications using the "eMbedded" C variations or VB.NET in Visual Studio .NET 2003. After you compile your mobile application, you type your application's start page URL into the emulator.

You can find some of the most popular emulators at these locations:

YoSpace This is the place to start:www.yospace.com. They offer multiple, simultaneousWAP emulations, including a variety of models and manufacturers. You can emulate Sony, Nokia, Motorola, Siemens, and others all at once without having to switch among various emulation environments.

Ericsson http://www.ericsson.com/mobilityworld/sub/open/index.html

Go.America (includes BlackBerry devices) http://www.goamerica.net/partners/developers/index.html

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