实现关机-危险勿试(网上找的，仅自用，非原创)

using System;
using System.Runtime.InteropServices;

class shoutdown{
[StructLayout(LayoutKind.Sequential, Pack=1)]
internal struct TokPriv1Luid
{
public int Count;
public long Luid;
public int Attr;
}

[DllImport("kernel32.dll", ExactSpelling=true)]
internal static extern IntPtr GetCurrentProcess();

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

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

[DllImport("advapi32.dll", ExactSpelling=true, SetLastError=true)]
internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall,
ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen);

[DllImport("user32.dll", ExactSpelling=true, SetLastError=true)]
internal static extern bool ExitWindowsEx(int flg, int rea);

internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
internal const int TOKEN_QUERY = 0x00000008;
internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;
internal const string SE_SHUTDOWN_NAME = "SeShutdownPrivilege";
internal const int EWX_LOGOFF = 0x00000000;
internal const int EWX_SHUTDOWN = 0x00000001;
internal const int EWX_REBOOT = 0x00000002;
internal const int EWX_FORCE = 0x00000004;
internal const int EWX_POWEROFF = 0x00000008;
internal const int EWX_FORCEIFHUNG = 0x00000010;

private static void DoExitWin(int flg)
{
bool ok;
TokPriv1Luid tp;
IntPtr hproc = GetCurrentProcess();
IntPtr htok = IntPtr.Zero;
ok = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES|TOKEN_QUERY, ref htok);
tp.Count = 1;
tp.Luid = 0;
tp.Attr = SE_PRIVILEGE_ENABLED;
ok = LookupPrivilegeValue(null, SE_SHUTDOWN_NAME, ref tp.Luid);
ok = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
ok = ExitWindowsEx(flg, 0);
}

public static void Main()
{
Console.WriteLine("正在关闭计算机……");
// 修改 EWX_SHUTDOWN 或者 EWX_LOGOFF, EWX_REBOOT等实现不同得功能。
// 在XP下可以看到帮助信息，以得到不同得参数
// SHUTDOWN /?
DoExitWin(EWX_SHUTDOWN);
}
}