n a previous article, I discussed developing mobile applications using the Microsoft Mobile Internet Toolkit (now renamed "ASP.NET Mobile Controls"). Microsoft designed the ASP.NET Mobile Controls to help developers build applications that run on devices with limited processing power, such as mobile phones, where much of the application logic resides on back-end Web servers.

In contrast, the .NET Compact Framework (.NET CF) is a scaled-down version of the .NET Framework, which you use to build applications that run on specific mobile devices with sufficient processing power. .NET CF supports only devices running Microsoft operating systems—specifically, Windows CE 3.0 (used in Pocket PC 2000 and Pocket PC 2002 platforms) and Windows CE.NET. The idea behind .NET CF is that it provides a familiar environment for desktop developers to build applications for mobile devices. This article shows you how to use Visual Studio to develop mobile applications that run on the Pocket PC.

Figure 1. To create a new Smart Device Application project, select the appropriate template to from the New Project dialog.

Developing a Pocket PC Application
In this article, you'll see how to build a Pocket PC application using Microsoft Visual Studio .NET 2003 (currently in final beta, but due to be released in early 2003). The sample application described in this article is a text editor that lets users check for word definitions, spell-check words, and translate text to different languages. All these capabilities are available via live Web services.

Figure 2. Choose the project type from the Smart Device Application Wizard.

To get started, you first create a new Smart Device Application project using your preferred language (the sample code uses Visual Basic .NET). Figure 1 shows the New Project dialog.

Selecting the Smart Device Application template launches the Smart Device Application Wizard, which asks you to select a platform and project for the application you want to build. For this project, choose Pocket PC and Windows Application (see Figure 2).

As you can see in Figure 3, the Visual Studio environment when developing a Pocket PC application is very similar to developing a Windows application.

Figure 3. The Visual Studio .NET interface loaded with a new .NET CF application.

The familiar Toolbox contains the available .NET CF controls, which are a subset of the Windows Form controls. One vital fact to bear in mind when building .NET CF projects is that not all the methods and classes in the full .NET Framework are available in .NET CF. Due to the limited processing power inherent in mobile devices, the .NET CF team at Microsoft removed a large subset of the methods available in the full .NET framework. The resulting lean .NET CF framework runtime requires a mere 1.5MB footprint.