C# - How to detect a Windows shutdown/logoff and cancel that action (after asking the user)

c# .net windows system-shutdown
Sébastien Nussbaumer picture Sébastien Nussbaumer · Jan 6, 2011 · Viewed 18.4k times · Source

Some explanation: for a project I'm working on I have to write a program that is running in the background, detects changes to files, and uploads the modified files to a web service to make it available to others. Quite simple synchronization if it were not for the case when a user modifies a big file and decides to shutdown its computer right after the edit.

I could cancel the upload and wait for the next reboot to do the upload, but I can imagine the user downloading the file from the web to another computer the next morning and don't understanding why his changes from last night aren't there.

So my idea was to detect when the users logs off or reboots Windows, and if I'm in the middle of an upload, just asking the user "We're still synchronizing file Foo.txt that you just changed. Are you sure you want to reboot ? You're changes won't be available to others until you restart your computer !". If the users says no, I'd need to cancel the reboot/loging off

Is this possible?

Answer

Adam Houldsworth picture Adam Houldsworth · Jan 6, 2011

There is a static class called SystemEvents that exposes this behaviour:

http://msdn.microsoft.com/en-us/library/microsoft.win32.systemevents.aspx

However, it cannot differentiate between certain actions and doesn't pause the OS process time-out guard. I used it once, but the default time-out as configured in the registry is a little short so will likely need increasing.

To cut a long story short, it all felt a little hackish.

Related questions

How to detect Windows shutdown or logoff

I need to detect when Windows is shutdown (or restarted) or when the user is logging off. I need to properly close the application before the application is closed. I noticed that no exit application event is raised when Windows …

Read More
How to delete a file after checking whether it exists

How can I delete a file in C# e.g. C:\test.txt, although apply the same kind of method like in batch files e.g. if exist "C:\test.txt" delete "C:\test.txt" else return nothing (ignore)

Read More
How do I start a process from C#?

How do I start a process, such as launching a URL when the user clicks a button?

Read More