C# 中使得windows 2000/XP关机代码

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);  } }

windows应用程序中，上面Main()以前的代码需要放在下面这段代码的前面:
[STAThread]
static void Main()
 {
.......
..................}