~请教怎么检测系统关机

求助~请问如何检测系统关机？
如题~请教下各位大哥，我的程序如何能检测到系统在关机呢？以便在关机前弹出提示：“正在关机。。。”

[解决办法]
拦截系统关机消息：

’以下在Form

Private Sub Form_Load()

　Dim ret As Long

　’记录原来的Window Procedure的位址

　preWinProc = GetWindowLong(Me.hwnd, GWL_WNDPROC)

　’设定form的window Procedure到wndproc

　ret = SetWindowLong(Me.hwnd, GWL_WNDPROC, AddressOf wndproc)

End Sub

Private Sub Form_Unload(Cancel As Integer)

　Dim ret As Long

　’取消 Message 拦截，而使之又只送往原来的Window Procedure

　ret = SetWindowLong(Me.hwnd, GWL_WNDPROC, preWinProc)
　
End Sub


’以下在.Bas

Option Explicit

Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long

Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Public Const GWL_WNDPROC = (-4)

Public Const WM_ENDSESSION = &H16

Public Const WM_QUERYENDSESSION = &H11

Public preWinProc As Long

Public Function wndproc(ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Dim blnShutdown As Boolean
　If Msg = WM_QUERYENDSESSION Then

　 　Debug.Print "QryEnd", wParam, lParam

　Else

　　If Msg = WM_ENDSESSION Then

　　　If wParam 0 Then ’代表将顺利关机或LogOff，这时便得做正常结束程序的操作

　　　　　blnShutdown = True 

　　　End If

　　End If

　End If

　’将之送往原来的Window Procedure

　wndproc = CallWindowProc(preWinProc, hwnd, Msg, wParam, lParam)

If blnShutdown Then MsgBox "Shutdown ..."
End Function
[解决办法]

VB code

Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)    If UnloadMode = vbAppWindows Then        MsgBox "正在关机。。。"    End IfEnd Sub
[解决办法]
1楼是大姐，不是大哥！