System.Runtime.InteropServices.UnmanagedType.IDispatch

This is the interface used for all COM objects
This is derived from the IUnknown interface.

Methods

There are four additional methods:
GetTypeInfoCount - can be 1 or 0 and represents the number of type information interfaces that the object provides
GetTypeInfo - returns the type information for the object
GetIDsOfNames - returns the DispIds that correspond to the method names. A DispId is an attribute that is used for any properties and methods that are exposed to COM
Invoke - provides access to the properties and methods of the object