拉布拉多幼犬照片:[VB]为什么使用 ExitWindowsEx 函数没办法实现关闭计算机

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

NT以上的操作系统还要调整程序的权限，使你的程序具有ShutDown的权限，所以还需要几个API：
OpenProcessToken
LookupPrivilegeValue
AdjustTokenPrivileges

你是98的代码,举人是2000/xp的代码.