The HDN_TRACK notification message notifies a header control's parent window that the user is dragging a divider in the header control. This notification message is sent in the form of a WM_NOTIFY message.
HDN_TRACK
phdr = (HD_NOTIFY FAR *) lParam;
Parameters
phdr
Pointer to an HD_NOTIFY structure that contains information about the header control and the item whose divider is being dragged.
Return Values
Returns FALSE to continue tracking the divider or TRUE to end tracking.
See Also