Unmanaged API reference (Office development in Visual Studio)
Starting with the 2007 Microsoft Office system, Office applications use the IManagedAddin interface interface to call into a VSTO Add-in loader component that is included with the Visual Studio Tools for Office runtime . This component is used to help load-managed VSTO Add-ins. You can create your own VSTO Add-in loader component by implementing this interface.
Note
Interested in developing solutions that extend the Office experience across multiple platforms? Check out the new Office Add-ins model. Office Add-ins have a small footprint compared to VSTO Add-ins and solutions, and you can build them by using almost any web programming technology, such as HTML5, JavaScript, CSS3, and XML.
In this section
A COM interface that you can implement to load and unload managed VSTO Add-ins in Office applications.