About Notification Messages
HTML Help notification messages are sent from a help window to the window that you specify in an HtmlHelp() call. Use notification messages to track a user's activities in a help window. For example, if you want to invoke an action when a user clicks the Refresh button on the toolbar, you could use the HHN_TRACK message.
Notification messages occur for the following events:
- When a user clicks a button on the toolbar or clicks a tab on the Navigation pane of the HTML Help Viewer, an HHN_TRACK message is sent that identifies the button or tab that was clicked.
- When a user navigates to a topic, an HHN_NAVCOMPLETE message is sent that identifies the topic navigated to.
- When a help window is created, an HHN_WINDOW_CREATE message is sent that identifies the window being created.
HTML Help sends notification messages from help windows that have the following HH_WINTYPE property settings:
- The value of hwndCaller must be non zero.
- The value of idNotify must be non zero.
- A value must be specified for HHWIN_PARAM_PROPERTIES in the fsValidProperties member.
- A value must be specified for HHWIN_PROP_TRACKING in the fsWinProperties member.
Notification messages are sent to the window specified in the hwndCaller parameter of the HtmlHelp() call.
HTML Help notification messages are sent via Windows WM_NOTIFY messages.
Note Notification messages are not sent if the value of hwndCaller is the desktop.
Build date: 4/14/2012