How to shut down the computer from C#

Works starting with windows XP, not available in win 2000 or lower:

This is the quickest way to do it:

Process.Start("shutdown","/s /t 0");

Otherwise use P/Invoke or WMI like others have said.

Edit: how to avoid creating a window

var psi = new ProcessStartInfo("shutdown","/s /t 0");psi.CreateNoWindow = true;psi.UseShellExecute = false;Process.Start(psi);

Taken from: a Geekpedia post

This method uses WMI to shutdown windows.

You'll need to add a reference to System.Management to your project to use this.

using System.Management;void Shutdown(){    ManagementBaseObject mboShutdown = null;    ManagementClass mcWin32 = new ManagementClass("Win32_OperatingSystem");    mcWin32.Get();    // You can't shutdown without security privileges    mcWin32.Scope.Options.EnablePrivileges = true;    ManagementBaseObject mboShutdownParams =             mcWin32.GetMethodParameters("Win32Shutdown");     // Flag 1 means we want to shut down the system. Use "2" to reboot.    mboShutdownParams["Flags"] = "1";    mboShutdownParams["Reserved"] = "0";    foreach (ManagementObject manObj in mcWin32.GetInstances())    {        mboShutdown = manObj.InvokeMethod("Win32Shutdown",                                        mboShutdownParams, null);    }}

This thread provides the code necessary: http://bytes.com/forum/thread251367.html

but here's the relevant code:

using System.Runtime.InteropServices;[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 IntPtrphtok );[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 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 );    }

Usage:

DoExitWin( EWX_SHUTDOWN );

or

DoExitWin( EWX_REBOOT );