Keep Alive the Machine - No Sleep

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Introduction

This is a very simple application that keeps the computer from sleeping. Nothing very fancy, but it seems useful when you cannot control the power options (managed by your domain admin) but you want your PC to stay awake occasionally.

Using the Code

    internal static class NativeMethods
    {
        // Import SetThreadExecutionState Win32 API and necessary flags
        [DllImport("kernel32.dll")]
        public static extern uint SetThreadExecutionState(uint esFlags);
        public const uint ES_CONTINUOUS = 0x80000000;
        public const uint ES_SYSTEM_REQUIRED = 0x00000001;
    }

public partial class MainForm : Form
    {
        private uint m_previousExecutionState;

        public MainForm()
        {
            InitializeComponent();
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            // Set new state to prevent system sleep (note: still allows screen saver)
            m_previousExecutionState = NativeMethods.SetThreadExecutionState(
                NativeMethods.ES_CONTINUOUS | NativeMethods.ES_SYSTEM_REQUIRED);
            if (0 == m_previousExecutionState)
            {
                MessageBox.Show("Failed to set system state.",  
        "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                // No way to recover; fail gracefully
                Close();
            }
        }

        protected override void OnClosed(System.EventArgs e)
        {
            base.OnClosed(e);

            // Restore previous state
            if (0 == NativeMethods.SetThreadExecutionState(m_previousExecutionState))
            {
                // No way to recover; already exiting
            }
        }
    }

Credits

• Delay's Blog

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)