Adding a Method (Visual C++)
You can use the Add Method Wizard to add a method to an interface in your project. If the project contains a class associated with the interface, the wizard modifies the class, too.
To add a method to your object
In Class View, expand the project node to display the interface to which you want to add the method.
You can also add methods to dispinterfaces, which, unless the project is attributed, are located under the library node.
Right-click the name of the interface.
On the shortcut menu, click Add, and then click Add Method.
In the Add Method Wizard, provide the information to create the method.
Specify any interface definition language settings for this method in the IDL attributes page of the wizard.
Click Finish to add the method.