C ＃ exit login if there is no operation

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace LockScreenMsg
{
    
    public partial class Form1 : Form
    {
    
        public Form1()
        {
    
            InitializeComponent();
            label1.Height = 200;
        }

        [StructLayout(LayoutKind.Sequential)]
        struct LASTINPUTINFO
        {
    
            [MarshalAs(UnmanagedType.U4)]
            public int cbSize;
            [MarshalAs(UnmanagedType.U4)]
            public uint dwTime;
        }

        [DllImport("user32.dll")]
        static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);

        static long GetLastInputTime()
        {
    
            LASTINPUTINFO vLastInputInfo = new LASTINPUTINFO();
            vLastInputInfo.cbSize = Marshal.SizeOf(vLastInputInfo);
            if (!GetLastInputInfo(ref vLastInputInfo))
            {
    
                return 0;
            }
            return Environment.TickCount - (long)vLastInputInfo.dwTime;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
    
            timer1.Enabled = true;
        }

        public string isNull = null;
        private void timer1_Tick(object sender, EventArgs e)
        {
    
           long time=GetLastInputTime()/1000;
            
            this.label1.Text = string.Format(" Users have {0} Seconds no operation ", time);
           if (time >= 20)
           {
    
                this.Close();
           }
        }
    }
}

Reference resources

https://www.cnblogs.com/snail0404/p/6433125.html