About IDO extension classes

An IDO extension class is a .NET class that allows developers to extend the functionality of an existing IDO by adding methods and event handlers. IDO extension classes are compiled into a .NET class library assembly and stored in the IDO metadata Objects Database. The IDO runtime loads these assemblies on demand and calls methods and event handlers in the extension classes in response to IDO requests.

An extension class is short-lived: It is created at the start of a request and disposed of immediately when the response is completed. Therefore, no state should be stored in an extension class.

Any public class in an IDO extension class assembly can be identified as the extension class for an IDO in the IDO metadata Objects Database. IDO extension class assemblies are .NET framework class libraries that are created using any of the .NET languages.