Question

Issue:
I have a WPF fullscreen application, which acts as a dashboard. The computer is in domain and domain policies enforce the computer to be locked in 10 minutes after the last user activity. I want to prevent the workstation (or desktop) from locking automatically.
An example of such behavior: Windows Media Player, which prevents this while a movie is running.

Known solutions (kinda workarounds):

1. It is possible to send a Win32 Mouse Move event every fixed interval of time (for example, every minute)
2. It is possible to send a key to the program (for example “Left Shift” key up) every fixed interval of time (for example, every minute)

QUESTION:
How can I prevent windows workstation from locking without using these workarounds?

Disclaimer:
I was pretty sure, there should be a similar question answered somewhere on StackOverflow, but i didn’t find any. I would appreciate, if you could point me into the right direction.

Answer 1

The solution has been pointed out through the comments, but I’m providing a simple starter solution for anyone else arriving via a web search:

/// <summary>
/// Interaction logic for App.xaml
/// </summary>
public partial class App : Application
{
    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    static extern EXECUTION_STATE SetThreadExecutionState(EXECUTION_STATE esFlags);

    public App()
    {
        InitializeComponent();

        App.Current.Startup += new StartupEventHandler((sender, e) =>
            {
                SetThreadExecutionState(EXECUTION_STATE.ES_DISPLAY_REQUIRED | EXECUTION_STATE.ES_CONTINUOUS);
            });
        App.Current.Exit += new ExitEventHandler((sender, e) =>
            {
                SetThreadExecutionState(EXECUTION_STATE.ES_CONTINUOUS);
            });
    }
}

[FlagsAttribute]
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
}

An alternative place to put the logic would be within an event handler for StateChanged on your main application window:

this.StateChanged += new EventHandler((sender, e) =>
    {
        if (WindowState == System.Windows.WindowState.Maximized)
        {
            SetThreadExecutionState(EXECUTION_STATE.ES_DISPLAY_REQUIRED | EXECUTION_STATE.ES_CONTINUOUS);
        }
        else
        {
            SetThreadExecutionState(EXECUTION_STATE.ES_CONTINUOUS);
        }
    });