How to get the system idle time in c# windows app?

To get idle use LASTINPUTINFO method. Here is the complete working sample code.

using System;

using System.Windows.Forms;

using System.Runtime.InteropServices;

namespace WinApp1

{

    public partial class Form3 : Form

    {

        LASTINPUTINFO lastInputInf = new LASTINPUTINFO();

        [DllImport("user32.dll")]

        public static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);

        [StructLayout(LayoutKind.Sequential)]

        public struct LASTINPUTINFO

        {

            [MarshalAs(UnmanagedType.U4)]

            public int cbSize;

            [MarshalAs(UnmanagedType.U4)]

            public int dwTime;

        }

        public Form3()

        {

            InitializeComponent();

        }

        private void Form3_Load(object sender, EventArgs e)

        {

            Timer dt = new Timer();

            dt.Tick += Timer_Tick;

            dt.Interval = 1000;

            dt.Start();

        }

      

        public void Timer_Tick(object sender, EventArgs e)

        {

            DisplayIdleTime();

        }

        public int GetIdleTime()

        {

            int idletime = 0;

            idletime = 0;

            lastInputInf.cbSize = Marshal.SizeOf(lastInputInf);

            lastInputInf.dwTime = 0;

            if (GetLastInputInfo(ref lastInputInf))

            {

                idletime = Environment.TickCount - lastInputInf.dwTime;

            }

            if (idletime != 0)

            {

                return idletime / 1000;

            }

            else

            {

                return 0;

            }

        }

        private void DisplayIdleTime()

        {

     

                label1.Text = "Idle time = " + " " + GetIdleTime().ToString() + " " + "seconds";

        }

    }

}