Implementing Event Extensions

To implement an event extension

1. Create a DLL that contains one or more extension objects.
2. Implement the following interfaces as noted:
   • IExchExt is required.
   • IExchExtSessionEvents if you want to customize the behavior when new messages are delivered.
   • IExchExtUserEvents if you want to handle changes to the currently-selected list box item, text, or object.
   • IExchExtMessageEvents if you want to customize the way Microsoft Exchange manipulates messages.
   • IExchExtAttachedFileEvents if you want to customize the handling of message file attachments.
3. Register for the appropriate context by placing an entry in the EXCHNG.INI file on 16-bit versions of Microsoft Windows or in the registry on Windows NT.

Extensions that handle events can be installed in the following contexts:

Additionally, user events, such as an object selection in a container, occur in the various message windows.

These events, divided into four categories and described in the following sections, are passed to the Microsoft Exchange client when they occur.