Defining a Notify Class

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Notify classes must be implemented so that they inherit from the INetCfgComponentControl interface. However, if notify objects perform certain operations their notify classes must also be implemented to inherit from the following interfaces:

  • If a notify object performs operations related to installing, upgrading, and removing the component that owns the object, the associated notify class must inherit from the INetCfgComponentSetup interface.

  • If a notify object displays custom property pages for the component that owns the object, the associated notify class must inherit from the INetCfgComponentPropertyUi interface.

  • If a notify object evaluates changes to the way the network configuration subsystem binds the component that owns the object to other network components, the associated notify class must inherit from the INetCfgComponentNotifyBinding interface.

  • If a notify object evaluates changes to network configuration that might affect the component that owns the object, the associated notify class must inherit from the INetCfgComponentNotifyGlobal interface.

Certain data members within notify classes should be defined as common to all notify objects. Certain data members should be defined as specific to their component. Data members that all notify objects should define include:

  • A pointer to an instance of the network component that owns the object of type INetCfgComponent interface. An instance of a notify object uses this pointer to access and control the component that owns the object.

  • A pointer to an instance of the network configuration object of type INetCfg interface. An instance of a notify object uses this pointer to access all aspects of network configuration.

  • Variables to store parameter information for the component that owns the notify object

  • A variable that specifies the action that a notify object previously performed. Define constants to indicate the different actions that notify objects might perform. When the network configuration subsystem calls the notify object's INetCfgComponentControl::ApplyRegistryChanges method to apply configuration changes to the registry, ApplyRegistryChanges uses this variable to determine how to make registry changes. For example, if a notify object previously performed operations relating to installing the component that owns the object in its INetCfgComponentSetup::Install method, Install should set this variable to indicate the action as install.

  • A registry key of type HKEY. A notify object calls the INetCfgComponent::OpenParamKey method of the component that owns the object to open and retrieve the registry key that contains parameters for the component. The notify object then sets the HKEY member to that key.

Define a constructor and a destructor for your notify class. Also consider defining private methods that only the notify class can use.

All the IUnknown interface methods should be implemented for a notify class. If a notify class inherits from any of the optional interfaces noted in the preceding list, all the methods of those interfaces must be implemented. Note that E_NOTIMPL is not a valid return type for any of the methods of the notify object interfaces. If a notify object does not require an implementation for a particular method, simply implement the method to return S_OK.