You cannot delete a class method that is currently participating in a mapping to an interface method. Removing the method would mean that the class did not correctly implement the interface (that is, it would be an illegal operation).
To remove the method, the current interface mapping must be transferred to another method (maintaining the contract that a class implements all methods supplied by an interface) or the class must cease implementing the interface. You can perform these actions by using the Interface Implementation Mapper dialog.
To stop the implementation of an interface
In the Class List of the Class Browser, select the class whose interface mapping implementation you want to stop.
Select the Interface Mapping command from the Classes menu. The Interface Implementation Mapper dialog, containing the current mapping details, is then displayed.
In the Available Interfaces list box, select the interface whose implementation you want to stop.
To transfer an interface mapping to another method, change the required mapping method in the second column of the table by entering a new method name or by selecting a complementary method from the drop-down list in the combo box.
Perform steps 5 through 8 under "Updating an Existing Interface Method Implementation", in the previous section, to change the method mapping implementation.
To remove an existing interface implementation from the class, click the Remove button. (This button is enabled only when they selected interface has been implemented for that class.) The Stop Implementing Interface message box is then displayed, prompting you to confirm that you want the specified class to stop implementing the specified interface.
Click the Yes button, to confirm that you want to stop the implementation. The Available Interfaces list box is then refreshed. If you click the No button, your interface mapping implementation is not removed.
Click the Close button.