Property page dialog procedures support property pages added by a provider. The procedures must adhere to the guidelines given for property sheets in the Microsoft Win32 Programmer's Reference. In particular, a dialog procedure must process any WM_NOTIFY messages appropriately.
A property page dialog procedure should also save the address of the DEVICE_INFO structure sent as the lParam parameter with the WM_INITDIALOG message. The Device Manager sends this structure to help the dialog procedure determine the device or class. Dialog procedures typically use the SetWindowLong to store this value in the DWL_USER portion of the window handle, then retrieve the address using the GetWindowLong function on subsequent messages.
If a reboot or restart is necessary due to the settings provided by the user, a dialog procedure show always set an appropriate value in the Flags member of the DEVICE_INFO structure. It must not send a PSN_GUISTART or PSN_REBOOT notification to the property sheet dialog procedure.