VSTO is included in the Visual Studio 2008 release, which is a set of related libraries and designers for developing applications, along with add-ins for Microsoft Office 2003 and 2007. Microsoft has bundled VSTO 3.0 with Visual Studio 2008 for the first time, which also represents a considerable step forward in the development environment. Previously, developers had to install Visual Studio and VSTO separately in order to build a development environment. Also, it was necessary to perform manual configuration in order to enable debugging for Office solutions.
Microsoft Office remains the best Office application when it comes to automating processes, as well as for using different types of data sources for presenting data to the user. In VSTO 3.0, Microsoft Office tools have become more powerful for presenting data from business applications because Microsoft has made the Office development environment more developer-friendly by creating a new development environment that helps developers to build solutions that function inside Office applications. Thus, Microsoft Office developers are able to easily create solutions that can do more for their business, while reducing costs by reusing existing functionality available in the Office applications.
VSTO can even integrate with your existing ERP system, and increase your enterprise's growth. One leading logistics company has integrated its existing enterprise application with Microsoft Office application using Visual Studio Tools for Office. You can extend your Office client applications by using VSTO and integrate VSTO with the SharePoint Portal to provide enterprise solutions such as Office Business Applications, including Customer Relationship Management, Supply Chain Management, and many others.
The preceding image represents Office 2007 and its extensibility using VSTO 3.0. All of the extensible features of VSTO 3.0 are not common to all of the Office 2007 applications. For example, application-level add-ins are not supported by Access 2007, and custom task panes are not supported by Visio 2007. VSTO documents contain a deployment manifest. The deployment manifest is an XML file that contains a description of the ClickOnce deployment, including the identification of and other information about the current ClickOnce application version that is to be deployed. The location of the VSTO document assembly will be available inside the document's deployment manifest. You can programmatically manipulate the deployment manifest of a document.
VSTO 3.0 is not a separate installation package for Visual Studio 2008. VSTO 3.0 reduces the development installation effort for Office developers. While installing Visual Studio 2008, VSTO 3.0 is installed along with the other frameworks and needed components.
The VSTO Runtime is installed when installing the Microsoft VSTO 3.0 redistributable package, which is essential for developing and deploying Office solutions using VSTO 3.0. A VSTO 3.0 redistributable package is the framework that brings the power and productivity of Visual Studio 2008 and the .NET framework to business solutions built on the Microsoft Office 2007 application.
The preceding image explains the version history of VSTO, highlighting some of the key differences between the versions. The current release of VSTO supports only the programming languages VB.NET and C#. We can expect other programming languages support in the next version of VSTO.