PSN_KILLACTIVE notification code

Notifies a page that it is about to lose activation either because another page is being activated or the user has clicked the OK button. This notification code is sent in the form of a WM_NOTIFY message.


    lppsn = (LPPSHNOTIFY) lParam; 



Pointer to a PSHNOTIFY structure that contains information about the notification code. This structure contains an NMHDR structure as its first member, hdr. The hwndFrom member of this NMHDR structure contains the handle to the property sheet. The lParam member of the PSHNOTIFY structure does not contain any information.

Return value

Returns TRUE to prevent the page from losing the activation, or FALSE to allow it.


An application handles this notification code to validate the information the user has entered.

Note  The property sheet is in the process of manipulating the list of pages when the PSN_KILLACTIVE notification code is sent. Do not attempt to add, remove, or insert pages while handling this notification code. Doing so will have unpredictable results.

To set a return value, the dialog box procedure for the page must call the SetWindowLong function with a DWL_MSGRESULT value set to the return value. The dialog box procedure must return TRUE.

If the dialog box procedure sets DWL_MSGRESULT to TRUE, it should display a message box to explain the problem to the user.


Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]