With powerful advances in recent years like the Microsoft Visual Studio 2005 automation model and the Microsoft Visual Studio 2008 Shell, Microsoft has increased support for customization of its Microsoft Visual Studio (IDE) integrated development environment by offering .NET developers broader extensibility. The .NET extensibility model in Microsoft Visual Studio 2010 takes it a step further.
The code editor and shell, rebuilt using managed code, enable new extensibility based on the Windows Presentation Foundation (WPF) graphics subsystem and extensible objects from the Managed Extensibility Framework (MEF) libraries, on which it's built. Part of the Microsoft .NET Framework 4 and Silverlight 4, MEF lets developers build tools around extension points - content types, classification types, drop handlers, tags, adornments, margins/scrolling and IntelliSense - using MEF components (parts), without implementing a package.
Microsoft Visual Studio 2010 also introduces VSIX deployment, a container model for extensions that's based on the Open Packaging Convention (OPC). OPC is used in the Microsoft Office System Open XML specification, which is supported in Office 2007 apps and other Microsoft software. It stores the extension and metadata about the extension - including manifest and payload - in a standard .ZIP file.
VSIX is part of the new Extension Manager in Microsoft Visual Studio 2010 that lets .NET developers manage extensions and share code templates, for example, in the Visual Studio Gallery from a menu within Microsoft Visual Studio 2010. The Extension Manager supports MEF components, VSPackages, project templates and item templates.
"For Microsoft Visual Studio 2010, the VSIX format supports VSPackages, MEF Components, Project Templates, Item Templates, Template Wizards, Toolbox Controls and custom extensions, extensions to a third-party extension," explained Gearard Boland, a developer on Microsoft's Visual Studio Platform team, in response to a similar question on an MSDN forum in February. "It does not support add-ins, Code Snippets and other extension types not listed in the previous point. VSIX also allows you to include assemblies and other resources that your extension requires in their payload and will install them next to your extension component."
Boland continued: "The benefit of switching to a VSIX-supported extension type is that you can take better advantage of the deployment and discoverability aspects that we delivered in Microsoft Visual Studio 2010 via the Extension Manager and Visual Studio Gallery integration."