如何控制电源键按下关机？

Question

I'm working on a kiosk style application where I need to control the shutdown/restart of the PC when the power button is pressed. Thanks to this post , I'm about 90% of the way there.

1. In control panel set the acpi power button press action to shutdown.
2. Listen for the WndProc message WM_QUERYENDSESSION

3. When received issue the completely undocumented:

    [DllImport("user32.dll", SetLastError = true)] static extern int CancelShutdown();

4. Return from the WndProc and bring up my own message box asking the user to Shutdown / Restart or Cancel, and respond to their action.

Everything works well if I do a start / shutdown from the task bar (I can issue theses as fast as I want). Everything also works well the first time I press the power button. On subsequent power button presses though I see a minute or so delay before I receive the WM_QUERYENDSESSION message.

Is there a setting or registry entry about how often windows will issue an ACPI event? I know it's not the hardware because under linux the same machine will fire the ACPI event as fast as I can press the button.

Thanks.

Answer 1

Calling in some favors at work, I was able to take this question directly to Microsoft support. On my third support engineer, I was essentially told this is not possible at an application level . It was his belief that calling the undocumented CancelShutdown() "confuses" the power manager or acpi driver which leads to the WM_QUERYENDSESSION message delay. Since the CancelShutdown() is undocumented, MS is not willing investigate further.

So, how do you hook power button presses? You need to write a device driver, specifically an ACPI Filter Driver . We are investigating this now.

Answer 2

I don't think it is possible unless you speak with your hardware manufacturer or hardwire the start-button so that it doesn't send a signal to the hardware which handles this. You can only delay it but even that would not give you 100% guarantee I guess.

Windows 8.1 will (maybe) bring a Kiosk Mode. Maybe that is what you are looking for ;-)