试一下这个...HDN_BEGINTRACK 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 = (LPNMHEADER) lParam; Parameters phdn Address of an NMHEADER 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. Requirements Windows NT/2000: Requires Windows NT 3.51 or later Windows 95/98/Me: Requires Windows 95 or later Header: Declared in commctrl.h.
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 = (LPNMHEADER) lParam; Parameters
phdn
Address of an NMHEADER 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. Requirements
Windows NT/2000: Requires Windows NT 3.51 or later
Windows 95/98/Me: Requires Windows 95 or later
Header: Declared in commctrl.h.