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退出操作系统可以调用Windows API的ExitWindowsEx函数。在Win9x下，只要简单地调用ExitWindowsEx函数就可以实现关机或者重新启动。但是在Win 2000/XP下调用ExitWindowsEx函数时，还需要先调用AdjustTokenPrivileges函数。下面的例子在Win9x和Win 2000/XP下都可以使用。请参考程序中的注释。
例子：
1、建立一个窗体，在上面放置4个按钮，按钮设置如下：
控件 控件名 Caption属性
---------------------------------------------------
CommandButton cmdLogoff 注销
CommandButton cmdForceLogoff 强制注销
CommandButton cmdShutdown 关机
CommandButton cmdForceShutdown 强制关机
2、将下面的代码加入窗体中：
Option Explicit
Private Const EWX_LogOff As Long = 0
Private Const EWX_SHUTDOWN As Long = 1
Private Const EWX_REBOOT As Long = 2
Private Const EWX_FORCE As Long = 4
Private Const EWX_POWEROFF As Long = 8
'ExitWindowsEx函数可以退出登录、关机或者重新启动系统
Private Declare Function ExitWindowsEx Lib "user32" _
(ByVal dwOptions As Long, _
ByVal dwReserved As Long) As Long
'GetLastError函数返回本线程的最后一次错误代码。错误代码是按照线程
'储存的，多线程也不会覆盖其他线程的错误代码。
Private Declare Function GetLastError Lib "kernel32" () As Long
Private Const mlngWindows95 = 0
Private Const mlngWindowsNT = 1
Public glngWhichWindows32 As Long
' GetVersion返回操作系统的版本。
Private Declare Function GetVersion Lib "kernel32" () As Long
Private Type LUID
UsedPart As Long
IgnoredForNowHigh32BitPart As Long
End Type
Private Type LUID_AND_ATTRIBUTES
TheLuid As LUID
Attributes As Long
End Type
Private Type TOKEN_PRIVILEGES
PrivilegeCount As Long
TheLuid As LUID
Attributes As Long
End Type
'GetCurrentProcess函数返回当前进程的一个句柄。
Private Declare Function GetCurrentProcess Lib "kernel32" () As Long
'OpenProcessToken函数打开一个进程的访问代号。
Private Declare Function OpenProcessToken Lib "advapi32" _
(ByVal ProcessHandle As Long, _
ByVal DesiredAccess As Long, _
TokenHandle As Long) As Long
'LookupPrivilegeValue函数获得本地唯一的标示符(LUID)，用于在特定的系统中
'表示特定的优先权。
Private Declare Function LookupPrivilegeValue Lib "advapi32" _
Alias "LookupPrivilegeValueA" _
(ByVal lpSystemName As String, _
ByVal lpName As String, _
lpLuid As LUID) As Long
'AdjustTokenPrivileges函数使能或者禁用指定访问记号的优先权。
'使能或者禁用优先权需要TOKEN_ADJUST_PRIVILEGES访问权限。
Private Declare Function AdjustTokenPrivileges Lib "advapi32" _
(ByVal TokenHandle As Long, _
ByVal DisableAllPrivileges As Long, _
NewState As TOKEN_PRIVILEGES, _
ByVal BufferLength As Long, _
PreviousState As TOKEN_PRIVILEGES, _
ReturnLength As Long) As Long
Private Declare Sub SetLastError Lib "kernel32" _
(ByVal dwErrCode As Long)
Private Sub AdjustToken()
'********************************************************************
'* 这个过程设置正确的优先权，以允许在Windows NT下关机或者重新启动。
'********************************************************************
Const TOKEN_ADJUST_PRIVILEGES = &H20
Const TOKEN_QUERY = &H8
Const SE_PRIVILEGE_ENABLED = &H2
Dim hdlProcessHandle As Long
Dim hdlTokenHandle As Long
Dim tmpLuid As LUID
Dim tkp As TOKEN_PRIVILEGES
Dim tkpNewButIgnored As TOKEN_PRIVILEGES
Dim lBufferNeeded As Long
'使用SetLastError函数设置错误代码为0。
'这样做，GetLastError函数如果没有错误会返回0
SetLastError 0
' GetCurrentProcess函数设置 hdlProcessHandle变量
hdlProcessHandle = GetCurrentProcess()
If GetLastError <> 0 Then
MsgBox "GetCurrentProcess error==" & GetLastError
End If
OpenProcessToken hdlProcessHandle, _
(TOKEN_ADJUST_PRIVILEGES Or TOKEN_QUERY), hdlTokenHandle
If GetLastError <> 0 Then
MsgBox "OpenProcessToken error==" & GetLastError
End If
' 获得关机优先权的LUID
LookupPrivilegeValue "", "SeShutdownPrivilege", tmpLuid
If GetLastError <> 0 Then
MsgBox "LookupPrivilegeValue error==" & GetLastError
End If
tkp.PrivilegeCount = 1 ' 设置一个优先权
tkp.TheLuid = tmpLuid
tkp.Attributes = SE_PRIVILEGE_ENABLED
' 对当前进程使能关机优先权
AdjustTokenPrivileges hdlTokenHandle, _
False, _
tkp, _
Len(tkpNewButIgnored), _
tkpNewButIgnored, _
lBufferNeeded
If GetLastError <> 0 Then
MsgBox "AdjustTokenPrivileges error==" & GetLastError
End If
End Sub
Private Sub cmdLogoff_Click()
ExitWindowsEx (EWX_LogOff), &HFFFF
MsgBox "ExitWindowsEx's GetLastError " & GetLastError
End Sub
Private Sub cmdForceLogoff_Click()
ExitWindowsEx (EWX_LogOff Or EWX_FORCE), &HFFFF
MsgBox "调用ExitWindowsEx函数后的GetLastError " & GetLastError
End Sub
Private Sub cmdShutdown_Click()
If glngWhichWindows32 = mlngWindowsNT Then
AdjustToken
MsgBox "调用AdjustToken后的GetLastError " & GetLastError
End If
ExitWindowsEx (EWX_SHUTDOWN), &HFFFF
MsgBox "调用ExitWindowsEx函数后的GetLastError " & GetLastError
End Sub
Private Sub cmdForceShutdown_Click()
If glngWhichWindows32 = mlngWindowsNT Then
AdjustToken
MsgBox "调用AdjustToken后的GetLastError " & GetLastError
End If
ExitWindowsEx (EWX_SHUTDOWN Or EWX_FORCE), &HFFFF
MsgBox "ExitWindowsEx's GetLastError " & GetLastError
End Sub
Private Sub Form_Load()
'********************************************************************
'* 当项目启动时，调用GetVersion检查操作系统。
'********************************************************************
Dim lngVersion As Long
lngVersion = GetVersion()
If ((lngVersion And &H80000000) = 0) Then
glngWhichWindows32 = mlngWindowsNT
MsgBox "在Windows NT或Windows 2000下运行"
Else
glngWhichWindows32 = mlngWindows95
MsgBox "在Windows 95/98/Me下运行"
End If
End Sub
3、编译成EXE，然后退出VB运行该EXE程序。
另外，可以参考徐景周的 Shutdown.zip例子。
关闭应用程序可以利用SendKeys语句向该程序发送Alt+F4键或利用Windows API的SendMessage函数发送WM_QUIT消息。
此问题由李海回答。
附加关键字：编程, 源程序, programming, source code, Visual Basic, VB, 其他方面, , Windows API, win32, api, windows api, gdi32, kernel。
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如何利用VB实现操作系统或者某一应用程序的自动关闭
