# C#/WPF - Monitor Switcher

**URL:** <https://forum.kirupa.com/t/c-wpf-monitor-switcher/215314>\
**Category:** open source\
**Created:** [February 6, 2007, 8:15am UTC](https://forum.kirupa.com/t/c-wpf-monitor-switcher/215314 "2007-02-06T08:15:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![kirupa](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/kirupa/32/11616_2.png) [@kirupa](https://forum.kirupa.com/u/kirupa)\
**Post date:** [February 6, 2007, 8:15am UTC](https://forum.kirupa.com/t/c-wpf-monitor-switcher/215314/1 "2007-02-06T08:15:28Z")

</div>

There are many situations where I want to turn my monitor off without putting my system into standby. For example, at night, I keep my system running to record shows on my Media Center, so I would want my monitors to turn off immediately. Manually turning them on/off by pushing their buttons isn’t a very efficient solution.

So, instead, I created an application that turns the monitor off at the push of a virtual button and turns them back on when the mouse moves. Here is how my application looks:

![](http://forum.kirupa.com/uploads/kirupa/3297/8710db683a08ace0.png)

You can install and run the application (XP/Vista) by clicking here: [**http://www.kirupafx.com/MonitorSwitcher/MonitorSwitcher.application**](http://www.kirupafx.com/MonitorSwitcher/MonitorSwitcher.application)

Because accessing the monitor requires lower-level Win32 calls, I used some resources on [http://www.pinvoke.net](http://www.pinvoke.net) to create a SendMessage call to access the monitor’s On/Off state. The code is:

```auto
using System;
using System.IO;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Navigation;
using System.Runtime.InteropServices;
using System.Windows.Input;
namespace MonitorSwitcher
{
 public partial class Window1
 {
        [DllImport("user32.dll")]
        public static extern int SendMessage(int hWnd, int Msg, int wParam, int lParam);
        const int SC_MONITORPOWER = 0xF170;
        const int WM_SYSCOMMAND = 0x0112;
        const int MONITOR_ON = -1;
        const int MONITOR_OFF = 2;
        const int MONITOR_STANBY = 1;
        int onFlag = 0;
  public Window1()
  {
   this.InitializeComponent();
  }
        private void MonitorOff(object sender, RoutedEventArgs e)
        {
            SendMessage(-1, WM_SYSCOMMAND, SC_MONITORPOWER, MONITOR_OFF);
            onFlag = 1;
        }
        private void MonitorOn(object sender, MouseEventArgs e)
        {
            if (onFlag == 1)
            {
                SendMessage(-1, WM_SYSCOMMAND, SC_MONITORPOWER, MONITOR_ON);
                onFlag = 0;
            }
        }
 }
}

```

I have attached the full source file for this below 🙂

Cheers!  
Kirupa :bandit: