Programming Visual Basic for the Palm OS

Chapter 9. Piedmont

In this chapter, we look at the AppForge Piedmont Framework (henceforth referred to as Piedmont), a component SDK for Windows and handheld devices. Piedmont uses a component-based architecture to bring portable component-oriented programming to the PDA.^[60] As powerful as COM is for Windows platforms, it is useless on the PDA, since so much of COM relies on support from the Windows operating system. AppForge bridges this gap on the Palm through BoosterPlus, which provides the registration and runtime support services associated with COM.

Piedmont is portable in a number of ways, which is useful in development, integration, and deployment. Piedmont object development is started with Microsoft’s Visual C++ environment. From there, the developer can continue to develop in Visual C++, debugging and testing his/her component from within Windows. At some point, the component is integrated into a Visual Basic AppForge project, or deployed on the handheld for Piedmont clients to use. Deploying the component involves compiling it with MetroWerks CodeWarrior, installing it on the Palm, and registering it with the Booster.

This chapter provides an overview of the Piedmont internals by creating a sample server component. We then show how to integrate the component with an AppForge Visual Basic project.

Piedmont’s extensive framework makes it difficult to cover all aspects of Piedmont in one chapter. In this chapter, we focus on the internals, since developers will want ...