using System;
using System.Runtime.InteropServices;
然后是一系列的常量声明： protected const int SE_PRIVILEGE_ENABLED = 0x2;
protected const int TOKEN_QUERY = 0x8;
protected const int TOKEN_ADJUST_PRIVILEGES = 0x20;
protected const string SE_SHUTDOWN_NAME = "SeShutdownPrivilege";
protected const int EWX_LOGOFF = 0x0;
protected const int EWX_SHUTDOWN = 0x1;
protected const int EWX_REBOOT = 0x2;
protected const int EWX_FORCE = 0x4;
protected const int EWX_POWEROFF = 0x8;
protected const int EWX_FORCEIFHUNG = 0x10;
定义Luid结构，注意属性： [StructLayout(LayoutKind.Sequential, Pack=1)]
protected struct LuidStruct {
    public int Count;
    public long Luid;
    public int Attr;
}
外部非托管DLL的声明： [DllImport("kernel32.dll", ExactSpelling=true)]
protected static extern IntPtr GetCurrentProcess();

[DllImport("advapi32.dll", SetLastError=true)]
protected static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr phtok);

[DllImport("advapi32.dll", SetLastError=true)]
protected static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);

[DllImport("advapi32.dll", SetLastError=true, ExactSpelling=true)]
protected static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall, ref LuidStruct newst, int len, IntPtr prev, IntPtr relen);

[DllImport("user32.dll", SetLastError=true, ExactSpelling=true)]
protected static extern bool ExitWindowsEx(int flg, int rea);
在NT级的操作系统上，需要先通知Windows系统即将关机，并且要获得关机的权限

以下就是关机、重启以及注销的实现： protected static void DoExitWindows(int flg) {
    LuidStruct tp;
    IntPtr hproc = GetCurrentProcess();
    IntPtr htok = IntPtr.Zero;

    OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok);
    tp.Count = 1;
    tp.Luid = 0;
    tp.Attr = SE_PRIVILEGE_ENABLED;
    LookupPrivilegeValue(null, SE_SHUTDOWN_NAME, ref tp.Luid);
    AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
    ExitWindowsEx(flg, 0);
}

public static void Shutdown() {
    DoExitWindows(EWX_SHUTDOWN);
}

public static void Reboot() {
    DoExitWindows(EWX_REBOOT | EWX_FORCE);
}

public static void Logoff() {
    DoExitWindows(EWX_LOGOFF);
}