How to shut down the computer from C#

Question

What's the best way to shut down the computer from a C# program?

I've found a few methods that work - I'll post them below - but none of them are very elegant. I'm looking for something that's simpler and natively .net.

Answer 1

The old-school ugly method. Use the ExitWindowsEx function from the Win32 API.

using System.Runtime.InteropServices;

void Shutdown2()
{
    const string SE_SHUTDOWN_NAME = "SeShutdownPrivilege";
    const short SE_PRIVILEGE_ENABLED = 2;
    const uint EWX_SHUTDOWN = 1;
    const short TOKEN_ADJUST_PRIVILEGES = 32;
    const short TOKEN_QUERY = 8;
    IntPtr hToken;
    TOKEN_PRIVILEGES tkp;

    // Get shutdown privileges...
    OpenProcessToken(Process.GetCurrentProcess().Handle, 
          TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, out hToken);
    tkp.PrivilegeCount = 1;
    tkp.Privileges.Attributes = SE_PRIVILEGE_ENABLED;
    LookupPrivilegeValue("", SE_SHUTDOWN_NAME, out tkp.Privileges.pLuid);
    AdjustTokenPrivileges(hToken, false, ref tkp, 0U, IntPtr.Zero, 
          IntPtr.Zero);

    // Now we have the privileges, shutdown Windows
    ExitWindowsEx(EWX_SHUTDOWN, 0);
}

// Structures needed for the API calls
private struct LUID
{
    public int LowPart;
    public int HighPart;
}
private struct LUID_AND_ATTRIBUTES
{
    public LUID pLuid;
    public int Attributes;
}
private struct TOKEN_PRIVILEGES
{
    public int PrivilegeCount;
    public LUID_AND_ATTRIBUTES Privileges;
}

[DllImport("advapi32.dll")]
static extern int OpenProcessToken(IntPtr ProcessHandle, 
                     int DesiredAccess, out IntPtr TokenHandle);

[DllImport("advapi32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool AdjustTokenPrivileges(IntPtr TokenHandle,
    [MarshalAs(UnmanagedType.Bool)]bool DisableAllPrivileges,
    ref TOKEN_PRIVILEGES NewState,
    UInt32 BufferLength,
    IntPtr PreviousState,
    IntPtr ReturnLength);

[DllImport("advapi32.dll")]
static extern int LookupPrivilegeValue(string lpSystemName, 
                       string lpName, out LUID lpLuid);

[DllImport("user32.dll", SetLastError = true)]
static extern int ExitWindowsEx(uint uFlags, uint dwReason);

In production code you should be checking the return values of the API calls, but I left that out to make the example clearer.

Answer 2

Short and sweet. Call an external program:

    using System.Diagnostics;

    void Shutdown()
    {
        Process.Start("shutdown.exe", "-s -t 00");
    }

Note: This calls Windows' Shutdown.exe program, so it'll only work if that program is available. You might have problems on Windows 2000 (where shutdown.exe is only available in the resource kit) or XP Embedded.

Answer 3

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

Should work.

For restart, it's /r

This will restart the PC box directly and cleanly, with NO dialogs.

Answer 4

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);
    }
}

Answer 5

I had trouble trying to use the WMI method accepted above because i always got privilige not held exceptions despite running the program as an administrator.

The solution was for the process to request the privilege for itself. I found the answer at http://www.dotnet247.com/247reference/msgs/58/292150.aspx written by a guy called Richard Hill.

I've pasted my basic use of his solution below in case that link gets old.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Management;
using System.Runtime.InteropServices;
using System.Security;
using System.Diagnostics;

namespace PowerControl
{
    public class PowerControl_Main
    {


        public void Shutdown()
        {
            ManagementBaseObject mboShutdown = null;
            ManagementClass mcWin32 = new ManagementClass("Win32_OperatingSystem");
            mcWin32.Get();

            if (!TokenAdjuster.EnablePrivilege("SeShutdownPrivilege", true))
            {
                Console.WriteLine("Could not enable SeShutdownPrivilege");
            }
            else
            {
                Console.WriteLine("Enabled SeShutdownPrivilege");
            }

            // 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
            mboShutdownParams["Flags"] = "1";
            mboShutdownParams["Reserved"] = "0";

            foreach (ManagementObject manObj in mcWin32.GetInstances())
            {
                try
                {
                    mboShutdown = manObj.InvokeMethod("Win32Shutdown",
                                                   mboShutdownParams, null);
                }
                catch (ManagementException mex)
                {
                    Console.WriteLine(mex.ToString());
                    Console.ReadKey();
                }
            }
        }


    }


    public sealed class TokenAdjuster
    {
        // PInvoke stuff required to set/enable security privileges
        [DllImport("advapi32", SetLastError = true),
        SuppressUnmanagedCodeSecurityAttribute]
        static extern int OpenProcessToken(
        System.IntPtr ProcessHandle, // handle to process
        int DesiredAccess, // desired access to process
        ref IntPtr TokenHandle // handle to open access token
        );

        [DllImport("kernel32", SetLastError = true),
        SuppressUnmanagedCodeSecurityAttribute]
        static extern bool CloseHandle(IntPtr handle);

        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int AdjustTokenPrivileges(
        IntPtr TokenHandle,
        int DisableAllPrivileges,
        IntPtr NewState,
        int BufferLength,
        IntPtr PreviousState,
        ref int ReturnLength);

        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern bool LookupPrivilegeValue(
        string lpSystemName,
        string lpName,
        ref LUID lpLuid);

        [StructLayout(LayoutKind.Sequential)]
        internal struct LUID
        {
            internal int LowPart;
            internal int HighPart;
        }

        [StructLayout(LayoutKind.Sequential)]
        struct LUID_AND_ATTRIBUTES
        {
            LUID Luid;
            int Attributes;
        }

        [StructLayout(LayoutKind.Sequential)]
        struct _PRIVILEGE_SET
        {
            int PrivilegeCount;
            int Control;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)] // ANYSIZE_ARRAY = 1
            LUID_AND_ATTRIBUTES[] Privileges;
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct TOKEN_PRIVILEGES
        {
            internal int PrivilegeCount;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]
            internal int[] Privileges;
        }
        const int SE_PRIVILEGE_ENABLED = 0x00000002;
        const int TOKEN_ADJUST_PRIVILEGES = 0X00000020;
        const int TOKEN_QUERY = 0X00000008;
        const int TOKEN_ALL_ACCESS = 0X001f01ff;
        const int PROCESS_QUERY_INFORMATION = 0X00000400;

        public static bool EnablePrivilege(string lpszPrivilege, bool
        bEnablePrivilege)
        {
            bool retval = false;
            int ltkpOld = 0;
            IntPtr hToken = IntPtr.Zero;
            TOKEN_PRIVILEGES tkp = new TOKEN_PRIVILEGES();
            tkp.Privileges = new int[3];
            TOKEN_PRIVILEGES tkpOld = new TOKEN_PRIVILEGES();
            tkpOld.Privileges = new int[3];
            LUID tLUID = new LUID();
            tkp.PrivilegeCount = 1;
            if (bEnablePrivilege)
                tkp.Privileges[2] = SE_PRIVILEGE_ENABLED;
            else
                tkp.Privileges[2] = 0;
            if (LookupPrivilegeValue(null, lpszPrivilege, ref tLUID))
            {
                Process proc = Process.GetCurrentProcess();
                if (proc.Handle != IntPtr.Zero)
                {
                    if (OpenProcessToken(proc.Handle, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY,
                    ref hToken) != 0)
                    {
                        tkp.PrivilegeCount = 1;
                        tkp.Privileges[2] = SE_PRIVILEGE_ENABLED;
                        tkp.Privileges[1] = tLUID.HighPart;
                        tkp.Privileges[0] = tLUID.LowPart;
                        const int bufLength = 256;
                        IntPtr tu = Marshal.AllocHGlobal(bufLength);
                        Marshal.StructureToPtr(tkp, tu, true);
                        if (AdjustTokenPrivileges(hToken, 0, tu, bufLength, IntPtr.Zero, ref ltkpOld) != 0)
                        {
                            // successful AdjustTokenPrivileges doesn't mean privilege could be changed
                            if (Marshal.GetLastWin32Error() == 0)
                            {
                                retval = true; // Token changed
                            }
                        }
                        TOKEN_PRIVILEGES tokp = (TOKEN_PRIVILEGES)Marshal.PtrToStructure(tu,
                        typeof(TOKEN_PRIVILEGES));
                        Marshal.FreeHGlobal(tu);
                    }
                }
            }
            if (hToken != IntPtr.Zero)
            {
                CloseHandle(hToken);
            }
            return retval;
        }

    }
}

Answer 6

There is no .net native method for shutting off the computer. You need to P/Invoke the ExitWindows or ExitWindowsEx API call.