<a target=_blank href="http://midsummerlgy.blog.163.com/blog/static/17191567120101120104615402/">原文地址：http://midsummerlgy.blog.163.com/blog/static/17191567120101120104615402/</a>

using System.Diagnostics;//首先导入这个命名空间
Process p = new Process();//实例化一个独立进程
p.StartInfo.FileName = "cmd.exe";//进程打开的文件为Cmd
p.StartInfo.UseShellExecute = false;//是否启动系统外壳选否
p.StartInfo.RedirectStandardInput = true;//这是是否从StandardInput输入
p.StartInfo.CreateNoWindow = true;//这里是启动程序是否显示窗体
p.Start();//启动
p.StandardInput.WriteLine("shutdown -s -t 10");//运行关机命令shutdown (-s)是关机 (-t)是延迟的时间 这里用秒计算 10就是10秒后关机p.StandardInput.WriteLine("exit");//退出cmd

原文地址：http://www.cnblogs.com/JohnXIe/archive/2008/07/24/1250852.html

public class ShutDown{[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;public 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);}}static void Main(string[] args){Console.WriteLine("正在关机……");// 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 /?ShutDown.DoExitWin(ShutDown.EWX_SHUTDOWN);}