PropertyHandle :: Modify - Mark property as modified

The function marks the instance selected in the property handle as modified. This is usually done automatically when assigning a value to a property handle. When, however, writing data directly to the instance the Modify() function must be called to register the modification. Otherwise the modification will not be stored to the database.

The function returns NO when executed successfully. When no instance is selected or in case of an error the function returns an error (YES).