How do I determine idle time in my C# application?

Question

I want to get the Windows Idle Time from my application. I am using exactly this code:

http://dataerror.blogspot.de/2005/02/detect-windows-idle-time.html

I h

Answer 1

Here is a sample code of how you can detect idle time in Windows. The definition of idle time here refer to the time when there is no user interaction with Windows such as no keyboard and mouse input.

Detecting idle time is used in application like MSN Messenger to change the status to "Away" after the user does not interact with the Windows for a predefine time.

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace GetLastInput_Demo
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class Form1 : System.Windows.Forms.Form
    {
        [DllImport("user32.dll")]
        static extern bool GetLastInputInfo(out LASTINPUTINFO plii);

        [StructLayout( LayoutKind.Sequential )]
        struct LASTINPUTINFO
        {
            public static readonly int SizeOf =
                   Marshal.SizeOf(typeof(LASTINPUTINFO));

            [MarshalAs(UnmanagedType.U4)]
            public int cbSize;   
            [MarshalAs(UnmanagedType.U4)]
            public int dwTime;
        }

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Timer timer1;
        private System.ComponentModel.IContainer components;

        public Form1()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();

        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }
        #region Windows Form Designer generated code
        private void InitializeComponent()
        {
            // Code is omitted here.
        }
        #endregion

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.Run(new Form1());
        }

        private void button1_Click(object sender, System.EventArgs e)
        {
            timer1.Enabled = !timer1.Enabled;
        }

        private void timer1_Tick(object sender, System.EventArgs e)
        {
            int idleTime = 0;
            LASTINPUTINFO lastInputInfo = new LASTINPUTINFO();
            lastInputInfo.cbSize = Marshal.SizeOf( lastInputInfo );
            lastInputInfo.dwTime = 0;

            int envTicks = Environment.TickCount;

            if( GetLastInputInfo( out lastInputInfo ) )
            {
                int lastInputTick = lastInputInfo.dwTime;
                idleTime = envTicks - lastInputTick;
            }

            int a;
           
            if(idleTime > 0)
               a = idleTime / 1000;
            else
               a = idleTime;

            label1.Text = a.ToString();
        }
    }
}

Answer 2

I took a slightly different approach to your method... This determines the idle time for your application, rather than using the system-wide idle time. I'm not sure if this meets your needs, however it might help you get further. It also has the benefit of being pure .NET instead of usingDllImport.

public partial class MyForm : Form, IMessageFilter {

    private Timer _timer;

    // we only need one of these methods...
    private DateTime _wentIdle;
    private int _idleTicks;

    public MyForm() {

        // watch for idle events and any message that might break idle
        Application.Idle += new EventHandler(Application_OnIdle);
        Application.AddMessageFilter(this);

        // use a simple timer to watch for the idle state
        _timer = new Timer();
        _timer.Tick += new EventHandler(Timer_Exipred);
        _timer.Interval = 1000;
        _timer.Start();

        InitializeComponent();
    }

    private void Timer_Exipred(object sender, EventArgs e) {
        TimeSpan diff = DateTime.Now - _wentIdle;

        // see if we have been idle longer than our configured value
        if (diff.TotalSeconds >= Settings.Default.IdleTimeout_Sec) {
            _statusLbl.Text = "We Are IDLE! - " + _wentIdle;
        }

        /**  OR  **/

        // see if we have gone idle based on our configured value
        if (++_idleTicks >= Settings.Default.IdleTimeout_Sec) {
            _statusLbl.Text = "We Are IDLE! - " + _idleTicks;
        }
    }

    private void Application_OnIdle(object sender, EventArgs e) {
        // keep track of the last time we went idle
        _wentIdle = DateTime.Now;
    }

    public bool PreFilterMessage(ref Message m) {
        // reset our last idle time if the message was user input
        if (isUserInput(m)) {
            _wentIdle = DateTime.MaxValue;
            _idleTicks = 0;

            _statusLbl.Text = "We Are NOT idle!";
        }

        return false;
    }

    private bool isUserInput(Message m) {
        // look for any message that was the result of user input
        if (m.Msg == 0x200) { return true; } // WM_MOUSEMOVE
        if (m.Msg == 0x020A) { return true; } // WM_MOUSEWHEEL
        if (m.Msg == 0x100) { return true; } // WM_KEYDOWN
        if (m.Msg == 0x101) { return true; } // WM_KEYUP

        // ... etc

        return false;
    }
}

I really have two methods for determining idle here... One using a DateTime object and one using a simple counter. You may find that one of these is better suited for your needs.

For the list of messages you may want to consider as user input, visit here.

Answer 3

    protected override void OnLoad(EventArgs e)
    {
    /* Check if we are in idle mode - No mouse movement for 2 minutes */
    System.Windows.Forms.Timer CheckIdleTimer = new                    System.Windows.Forms.Timer();
    CheckIdleTimer.Interval = 120000;
    CheckIdleTimer.Tick += new EventHandler(CheckIdleTimer_Tick);
    CheckIdleTimer.Start();
    }
    private void CheckIdleTimer_Tick(object sender, EventArgs e)
    {
    uint x = IdleTimeFinder.GetIdleTime();
    if (x > 120000) {
         //...do something
    }
    }


    public class IdleTimeFinder
    {
    [DllImport("User32.dll")]
    private static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);

    [DllImport("Kernel32.dll")]
    private static extern uint GetLastError();

    public static uint GetIdleTime()
    {
    LASTINPUTINFO lastInPut = new LASTINPUTINFO();
    lastInPut.cbSize     (uint)System.Runtime.InteropServices.Marshal.SizeOf(lastInPut);
    GetLastInputInfo(ref lastInPut);
    return ((uint)Environment.TickCount - lastInPut.dwTime);
    }

   public static long GetLastInputTime()
   {
    LASTINPUTINFO lastInPut = new LASTINPUTINFO();
    lastInPut.cbSize                (uint)System.Runtime.InteropServices.Marshal.SizeOf(lastInPut);
    if (!GetLastInputInfo(ref lastInPut))
    {
    throw new Exception(GetLastError().ToString());
    }
    return lastInPut.dwTime;
    }
    }


 internal struct LASTINPUTINFO
{
    public uint cbSize;

    public uint dwTime;
}