HDN_BEGINTRACK
The
HDN_BEGINTRACK notification message notifies a header control s parent window
that the user has begun dragging a divider in the control (that is, the user
has pressed the left mouse button while the mouse cursor is on a divider in the
header control). This notification message is sent in the form of a WM_NOTIFY
message.
HDN_BEGINTRACK
phdn = (HD_NOTIFY FAR *) lParam;
Parameters
phdn
Pointer to an
HD_NOTIFY structure that contains information about the header control
and the item whose divider is to be dragged.
Return Values
Returns FALSE
to allow tracking of the divider or TRUE to prevent tracking.
See Also
HD_NOTIFY, WM_NOTIFY