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FeatureEnterprise .NET for Smart DevicesIntroducing the .NET Compact Frameworkand Smart Device Extensions for VS.NETEVERYWHEREBY CHRISTIANFORSBERG& ANDREAS SJÖSTRÖMHOMEDESKTOPSERVER22if you want to extend yourexisting systems as wellas your knowledge of.NET development whilebuilding solutions for smart devices,the upcoming .NET CF (CompactFramework) and SDE (Smart DeviceExtensions) are definitely the way togo. In this article we provide anexample of how to implement amobile application that can work asan extension to your existing systems,and also show you how toextend your knowledge of .NETdevelopment.It’s perhaps more true than everthat mobile solutions rarely standalone. Most consumer-orientedapplications are created to work inan offline or disconnected mode,but for enterprise solutions theincreasing connectivity of newdevices opens up enormous possibilitiesfor online and “sometimesconnected” applications as well.When looking at real-world businessscenarios and the capabilitiesof current mobile devices, it’s obviousthat the options are greater thanjust offline or online. Specific userrequirements such as “how often?”and “at what bandwidth?” shoulddetermine where on the scale fromoffline to online we need to be (seeFigure 1).The more a mobile application isconnected, the thinner it can befrom an application logic and localstorage perspective. The less it’sconnected, the higher the demandon the application logic and localstorage. A typical online mobileapplication is a Web application targetedat smart device browsers likeInternet Explorer for Pocket PC.With a Web application there are nodeployment issues for the device, asthe browser is already in place.However, most other connectivityoptions (from “auto-connected” allthe way to “never connected”)require you to have a custom applicationrunning on the device.The need for connectivity alsoimplies that we’re most often talkingabout extending existing systems toanyplace. Many workers are currentlytied to a desk with a PC on awire. They would like to be free togo wherever they want, yet still beable to perform their duties. Is itasking too much to help those poorpeople out?Consider Some ExamplesLet’s take a simple scenario likereporting time. Many mobile workershave to specify how they spendtheir time during their work hours.This is a common task in an enterpriseenvironment, and many of usare familiar with the pain of “re-creating”the past week during theweekly reporting – late Sunday night– into our company’s central timereporting system. Why? Because wehave to wait until we find a PC that’swired to the company network.What if we could do it anyplace?And since we don’t need to do theactual reporting more than weekly,it would fall into the category “seldomconnected” (see Figure 1).What if we didn’t actually have to beconnected when we do it?Another issue is how we can helpthose workers get the new tools ofthe trade. What if we could use thesame knowledge that we alreadyhave in building our enterprisesolutions? In the not too distantfuture, most of those solutions usingMicrosoft technology will be developedfor .NET, and therefore itwould be great if we could extend.NET and .NET development skillsto build those solutions for mobiledevices. As you may already know,you’ll soon be able to do just that.Build a Business CaseIn defining how we can benefitfrom turning paper-based processesinto mobile solutions, the keywordsare speed and quality.First of all, since time is money,we want to save time. By savingtime we can get an instant paybackon the investment in most mobilesolutions. We can save time for themobile worker, and most probablyalso for the back-office personnelwho now enter submitted paperdata into a system. Perhaps mostimportantly, we could also save thetime between data entry and datausage. For example, if the timereported was submitted each dayinstead of each week, we couldexpedite invoices related to thattime.Second, we’ll collect the data at thesource, gaining speed in our businessand improving data quality. Writingdata on paper, then passing it tosomeone else to read and enter into asystem is probably the most certainway to achieve poor-quality data.Higher quality most often translates tosaved time, and also to improved relationshipswith customers, partners,and even employees.Preview Issue • dotnetdevelopersjournal.com
What we’re trying to say is that ifyou want to build a successfulmobile solution, do your homework– document the business casebehind the solution. Most often, ifyou just spend some time thinkingit through, it’s not very hard.Technology OverviewSo, what is enterprise .NETdevelopment for smart devices? Ifwe look at the connectivity optionsfor an application (see Figure 1), wesometimes want to build a thinbrowser-based Web application, inwhich case we would probably use atool like Microsoft Mobile InternetToolkit with ASP.NET. But for mostother connectivity options, we needsomething that provides a soliddevelopment environment on thedevice. This is why the upcomingrelease of the .NET CompactFramework and Smart DeviceExtensions for Visual Studio .NET(VS.NET) becomes interesting..NET CF is a subset of the full.NET Framework. Careful thoughthas been put into selecting theclasses that make the most sense ona mobile device, taking into accountthe smaller footprint required ondevices and the accompanyingmemory and performance restrictions.It includes a CLR targeted forsmart devices.SDE is a set of extensions toVS.NET that enable you to buildapplications for the .NET CF. Theextensions include profiles that customizeVS.NET for smart devicedevelopment. For example, whentargeting the .NET CF, you getIntelliSense for the supported classesand only supported controls areavailable in the toolbox.For enterprise developers, thismeans that we’ll now get back to theOfflineNeverConnectedf 1SeldomConnectedFigure 1: The offline/online scaleOftenConnecteddotnetdevelopersjournal.com • Preview Issuestate where there’s a single tool setfor building applications for PCsand smart devices like Pocket PCand the coming SmartPhone 2002.C# or VB.NET?There’s been much discussion onthe selection of a development languagefor VS.NET. As we’ve made achoice to implement our sampleapplication in C#, we’ve stated ourpremium choice of language.However, we think that all enterprise.NET developers will have tomanage development in both C#and VB.NET. Various projects will berun using each, and we think thatthe choice will most often be madein relation to historical issues ratherthan technical issues like performanceor productivity, or evenissues like speed of developmentand ease of maintenance.Traditional Visual C++ developersand even Java developers willprobably select C# as their premiumchoice, and we think that even Javadevelopers converting to C# willhave a less painful migration thanVisual Basic 6 developers will haveconverting to VB.NET.The interesting part of .NET isnot the languages, but the framework.Despite the excellent languageinteroperability in .NET, wedon’t recommend mixing languagesin the same project if youcan avoid it.Time Reporting ExampleTo show you what we mean,we’ve put together a sample applicationto report the time you spendon different activities. With this simpletool, you can report your timeanyplace and at any time.The opening screen of the sampleapplication (see Figure 2) showsAuto-ConnectedOnlineAlwaysConnectedf 2 Figure2: Time reporting applicationa list of times reported for differentactivities (usually projects), whichyou can manipulate with the Add,Edit, and Delete buttons. You usethe Save button to save all timesreported and exit the application.When you tap the Add or Editbutton, you’re presented with a newscreen (see Figure 3). Here you canreport or update an activity withdate, project, and hours spent.Obviously, you save with the OKbutton and abort with the Cancelbutton.The sample application allowsthe user to work offline using XMLfiles. The Project ComboBox (seeFigure 3) is filled from an XML file(projects.xml) and the reportedtime is saved in (and retrieved onstartup from) an XML file (timereport.xml).Code WalkthroughLet’s have a look at the code forthe sample application. As we’vealready stated, our choice of languagefor the sample is C#, and wehope that most VB.NET developerswill be able to follow the logic anyway.(Authors’ Note: We built our sampleapplication using prerelease versionsof Visual Studio .NET, .NETCompact Framework, and SmartDevice Extension, and therefore itmay not be compatible with thefinal release versions.)One of the core features of the.NET CF is native support for23
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