How to close the C# application when the computer is locked (window L)

// check below code it will automatically close the application whenever you locks the workstation by windows+L key, hope it solves your problem

using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication4
{
    public partial class Form1 : Form
    {
        private static SessionSwitchEventHandler eHandler;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            eHandler = new SessionSwitchEventHandler(EventCapture);
            SystemEvents.SessionSwitch += eHandler;
        }
        void EventCapture(object sender, SessionSwitchEventArgs e)
        {

            switch (e.Reason)
            {
                case SessionSwitchReason.SessionLock: MessageBox.Show("Lock Encountered"); this.Close(); break;
                case SessionSwitchReason.SessionUnlock: MessageBox.Show("UnLock Encountered"); break;
            }
        }
    }
}