PCの画面をオフにする

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace DisplayPowerOff
{
    /// <summary>
    /// PCのディスプレイをOFFにする。
    /// </summary>
    class Program
    {
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
        static extern IntPtr SendMessage(int hWnd, uint Msg, int wParam, int lParam);

        enum MonitorState
        {
            On = -1, Off = 2, StandBy = 1
        }

        public static void PowerOff()
        {
            SendMessage(-1, 0x112, 0xf170, (int)(MonitorState.Off));
        }
        static void Main(string[] args)
        {
            PowerOff();
        }
    }
}