Question

We have a service in our project that runs and we need it to get a command on log off. We could send a command via our console, but the console is a separate program which could not be running. It does not necessarily need to stop, but it does need to get a command of some sort. Is there anything with in the service which can catch a Log Off event?

[10/17/12 10:45] – The service is running as Local System.

[10/17/12 12:07] – I added the following method, but I am not getting any output when I log off or onto the computer even though I am successfully writing to the log with this message I will try again rebuilding my solution, but wanted to post this here in case I am doing something wrong.

protected override void OnSessionChange(SessionChangeDescription changeDescription)
{
        WriteToDebugLog(new string[] { "OnSessionChange()",
                                        DateTime.Now.ToLongTimeString() + " - Session change notice received: " + changeDescription.Reason.ToString() + "  Session ID: " + changeDescription.SessionId.ToString(),
                                       "Information" });
        base.OnSessionChange(changeDescription);
}

Answer 1

Unfortunately Services cannot run per-user, they’re system wide. You may modify your service to detect when the user log-off but then it won’t be started again when the user log-in again. As alternative you may use a second service to monitor log-in activity (using OnSessionChanged as pointed out by @rene) and to start/stop the first service according.

It’s a little bit tricky and you have to install a second service, I prefer a more simple solution using scripting.

PowerShell

You can use two PowerShell scripts, this is to start the service:

Start-Service -name "YourServiceName"

This is to stop the service:

Stop-Service -name "YourServiceName"

To configure this scripts to be executed take a look here. In short you have to change policy configuration in HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System!RunUserPSScriptsFirst to run your scripts when needed.

“Old” shell

You’re not forced to use PowerShell, to start/stop a service can be done using shell commands:

sc start YourServiceName

and

sc stop YourServiceName

See this post for how to execute a batch file (or a command) at log-off. In short you have to add an entry to HKCU\Software\Policies\Microsoft\Windows\System\Scripts\Logoff for log-off and HKCU\Software\Policies\Microsoft\Windows\System\Scripts\Logon for log-on (but there are many many different places where you can put your scripts for log-on).