Monitor Power Off, Import DLL?

[mattst]

I have 2 pieces of freeware (one dedicated, one a suite of utilities) that will turn my PC's monitor off. I like to be able to hit my monitor off with a double click on a desktop icon.

Both these pieces of freeware don't do the job properly (sometimes), so I thought I'd look in to writing such a utility myself and do it properly.

So I know it's possible to do, probably through importing a DLL, but I can't seem to find out which one.

Can someone point me in the right direction please?

Thanks.

[someuser77]

The right direction will be this thread.

And in C# it will look like this:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using HWND = System.IntPtr;
using BOOL = System.Int32;
using UINT = System.UInt32;
using WPARAM = System.IntPtr;
using LPARAM = System.IntPtr;

namespace ShutdownMonitor
{
    class Program
    {
        private enum SC_MONITORPOWEROptions : int
        {
            /// <summary>
            /// the display is powering on
            /// </summary>
            PowerOn = -1,
            /// <summary>
            /// the display is going to low power
            /// </summary>
            LowPower = 1,
            /// <summary>
            /// the display is being shut off
            /// </summary>
            ShutDown = 2
        }

        public static UINT WM_SYSCOMMAND = 0x112;
        public static WPARAM SC_MONITORPOWER = (System.IntPtr)0xF170;

        static void Main(string[] args)
        {
            
            HWND desktopWindow = GetDesktopWindow();
            BOOL result = PostMessage(desktopWindow, WM_SYSCOMMAND, SC_MONITORPOWER, (WPARAM)SC_MONITORPOWEROptions.LowPower);
            Console.WriteLine(result != 0);
        }

        [DllImport("user32.dll", EntryPoint = "PostMessage", SetLastError = true)]
        private static extern BOOL PostMessage(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam);

        [DllImport("user32.dll", EntryPoint = "GetDesktopWindow", SetLastError = true)]
        private static extern HWND GetDesktopWindow();
    }
}

If you are using Windows Forms than you can get the desktopWindow using the Form's Handle property.

[mattst]

What a comphrensive reply.

Thanks someuser. Cheers.

[mattst]

Thanks again someuser77.

I just got around to writing the software today, I want an icon on the notifications bar that I can use to turn the monitor off, and it's working a treat so far.

Cheers.

PS. If anyone finds this at a later date with a search and wants to know how to use a form's handle to get the desktop window then simply replace the first line below with the second. (Form applications only!!).

HWND desktopWindow = GetDesktopWindow();

HWND desktopWindow = this.Handle;

HTH.