COM Object Interfaces
IUnknown and IDispatch Interfaces
When you invoke the
actxserver function, MATLAB® creates the server and returns a handle to the server interface as a
means of accessing its properties and methods. The software uses the following
process to determine which handle to return:
First get a handle to the IUnknown interface from the component. All COM components are required to implement this interface.
Attempt to get the IDispatch interface. If IDispatch is implemented, return a handle to this interface. If IDispatch is not implemented, return the handle to IUnknown.
Components often provide additional interfaces, based on IDispatch, that are
implemented as properties. Like any other property, you obtain these interfaces
using the MATLAB
For example, a Microsoft® Excel® component contains numerous interfaces. To list these interfaces, along with Excel properties, type:
h = actxserver('Excel.Application'); get(h)
MATLAB displays information like:
Application: [1x1 Interface.Microsoft_Excel_9.0_ Object_Library._Application] Creator: 'xlCreatorCode' Parent: [1x1 Interface.Microsoft_Excel_9.0_ Object_Library._Application] ActiveCell:  ActiveChart: [1x50 char] . .
To see if
Workbooks is an interface, type:
w = h.Workbooks
w = Interface.Microsoft_Excel_9.0_Object_Library.Workbooks
The information displayed depends on the version of the Excel software you have on your system.
For examples using Excel in MATLAB, see: