HDN_BEGINTRACK Overview  Group

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