c# - How to interrupt Screen-saver under windows 8

Question

I would like know how to interrupt Screen-saver under the Windows 8(Embedded version) or Windows 10, Because a window(C#) of my project only run under the normal status, otherwise it will be error if run under Screen-saver. so I want to interrupt the Screen-saver before this window pop-up.

I have researched some solution and idea that included as below,

• a. Move mouse(used the user32's mouse_event api)
• b. Send keys(also used the user32's api)
• c. Kill screen-saver process.

Both of a & b are ways I have tried them and worked well on the windows 10, but not worked on the Windows 8(Embedded version), so currently I only focus on the c way, about way of c I searched the as below link,

https://support.microsoft.com/en-us/help/140723/how-to-force-a-screen-saver-to-close-once-started-in-windows-nt,-windows-2000,-and-windows-server-2003

https://www.codeproject.com/Articles/17067/Controlling-The-Screen-Saver-With-C

but above links still aren't work on the windows 10 and Windows 8(Embedded version), which expert give me some suggestion? thanks in advance.

Answer 1

Have a look at the unmanaged API functions GetSystemPowerStatus and SetThreadExecutionState. Using a (thread) timer, you can periodically update the status, e.g. from a class property, and inform the system about your requirements. This is useful, if your application may allow or disallow the screensaver, depending on it's operating state.

public class PowerManager : IDisposable
{
  [Flags]
  public enum ExecutionStateEnum : uint
  {
    LetTheSystemDecide    = 0x00,
    SystemRequired        = 0x01,
    SystemDisplayRequired = 0x02,
    UserPresent           = 0x04,
    Continuous            = 0x80000000,
  }

  [DllImport("kernel32")]
  private static extern uint SetThreadExecutionState(ExecutionStateEnum esFlags);

  public PowerManager() {}

  public Update(ExecutionStateEnum state)
  {
    SetThreadExecutionState(state);
  }
}

Update:

Then call PowerManager.Update(ExecutionStateEnum.SystemDisplayRequired) to disable the screensaver or call PowerManager.Update(ExecutionStateEnum.LetTheSystemDecide) to restore the default system behaviour (allow the screensaver). If the method is called periodically from a timer callback, adjust the timer interval according to the configured screensaver timeout.