ON_OFF_Monitor.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Security.Policy;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace scrn
{
    public partial class Form1 : Form
    {
        [DllImport("user32.dll")]
        static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);
        [DllImport("user32.dll")]
        static extern void mouse_event(Int32 dwFlags, Int32 dx, Int32 dy, Int32 dwData, UIntPtr dwExtraInfo);

        private const int WmSyscommand = 0x0112;
        private const int ScMonitorpower = 0xF170;
        private const int MonitorShutoff = 2;
        private const int MouseeventfMove = 0x0001;

        public static void MonitorOff(IntPtr handle)
        {
            SendMessage(handle, WmSyscommand, (IntPtr)ScMonitorpower, (IntPtr)MonitorShutoff);
        }

        private static void MonitorOn()
        {
            mouse_event(MouseeventfMove, 0, 1, 0, UIntPtr.Zero);
            Thread.Sleep(40);
            mouse_event(MouseeventfMove, 0, -1, 0, UIntPtr.Zero);
        }

  
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            var form = new Form();

            while (true)
            {
                Cursor.Position = new Point(Cursor.Position.X - 50, Cursor.Position.Y - 50);
                MonitorOff(form.Handle);
            }

        }
    }
}