PreventIdleTrigger.cs

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

namespace ConsoleApplication6
{
    class Program
    {
        static void Main(string[] args)
        {
            //PowerInfo.KeepSystemAwake();

            Timer aTimer = new Timer();
            aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
            aTimer.Interval = 5000;
            aTimer.Enabled = true;
            Console.ReadLine();
        }

        private static void OnTimedEvent(object sender, ElapsedEventArgs e)
        {
            int i = PowerInfo.GetIdleTimeRemaining();
            Console.WriteLine(i);

            if (i < 1800)
            {
                Console.WriteLine("Triggering SetExecutionState");
                PowerInfo.KeepSystemAwake();
            }
        }
    }

    class PowerInfo
    {
        public static int GetIdleTimeRemaining()
        {
            var info = new SYSTEM_POWER_INFORMATION();
            int ret = GetSystemPowerInformation(SystemPowerInformation, IntPtr.Zero, 0, out info, Marshal.SizeOf(info));
            if (ret != 0) throw new System.ComponentModel.Win32Exception(ret);
            return info.TimeRemaining;
        }

        public static void KeepSystemAwake()
        {
            SetThreadExecutionState(EXECUTION_STATE.ES_SYSTEM_REQUIRED);
        }

        private struct SYSTEM_POWER_INFORMATION
        {
            public int MaxIdlenessAllowed;
            public int Idleness;
            public int TimeRemaining;
            public byte CoolingMode;
        }
        private const int SystemPowerInformation = 12;
        private const int SystemExecutionState = 16;
        [DllImport("powrprof.dll", EntryPoint = "CallNtPowerInformation", CharSet = CharSet.Auto)]
        private static extern int GetSystemPowerInformation(int level, IntPtr inpbuf, int inpbuflen, out SYSTEM_POWER_INFORMATION info, int outbuflen);
        [DllImport("powrprof.dll", EntryPoint = "CallNtPowerInformation", CharSet = CharSet.Auto)]
        private static extern int GetSystemExecutionState(int level, IntPtr inpbuf, int inpbuflen, out int state, int outbuflen);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern EXECUTION_STATE SetThreadExecutionState(EXECUTION_STATE esFlags);
        [Flags]
        public enum EXECUTION_STATE : uint
        {
            ES_AWAYMODE_REQUIRED = 0x00000040,
            ES_CONTINUOUS = 0x80000000,
            ES_DISPLAY_REQUIRED = 0x00000002,
            ES_SYSTEM_REQUIRED = 0x00000001
            // Legacy flag, should not be used.
            // ES_USER_PRESENT = 0x00000004
        }
    }
}