Chapter 33. Office Applications

Microsoft Office applications have always been extensible via add-ins and various automation techniques. Even Visual Basic for Applications (VBA), which was widely known for various limitations in accessing system files, had the capability to write applications that used an instance of an Office application to achieve certain tasks, such as Word's spell-checking feature.

When Visual Studio .NET was released in 2002, Microsoft soon followed with the first release of Visual Studio Tools for Office (known by the abbreviation VSTO, pronounced visto). This initial version of VSTO didn't really produce anything new except for an easier way of creating application projects that would use Microsoft Word or Microsoft Excel. However, subsequent versions of VSTO quickly evolved and became more powerful, allowing you to build more functional applications that ran on the Office platform.

The latest version of VSTO was shipped as part of Visual Studio 2008. It provides significant enhancements over the previous version, including support for Office 2007 and the new Ribbon user interface, the ability to create application-level add-ins for Word, Excel, PowerPoint, Project, and Visio, and tools for building SharePoint workflows.

This chapter begins with a look at the types of applications you can build with VSTO. It then guides you through the process of creating a document-level customization to a Word document, including a custom Actions Pane. Following this, the chapter provides a walkthrough, showing how to create an Outlook add-in complete with an Outlook Form region. Finally, the chapter provides some important information regarding the debugging and deployment of Office applications.