C#: Simple Windows Service gives Security Exceptio

问题:

I am doing the walkthrough in the following link: http://msdn.microsoft.com/en-us/library/zt39148a%28VS.80%29.aspx

I have followed it exactly, line by line. I installed the service successfully, however, when I try to run it, the following error message appears:

"An unhandled exception ("System.Security.SecurityException') occurred in MyNewService.Exe [5292].

I have seen that for many people it works, but some people get this exception, though I could not find an answer. Does anyone have an idea? Thanks.

回答1:

The EventLog.SourceExists method is what will be causing this exception. The most common reason being it tries to access ALL the event logs (including the Security log) which by default in Vista you will not have permissions for. Another reason can be if the source you are looking for is not found in the event log (which I find rather odd!).

A work-around:

bool sourceFound = false;
try
{
    sourceFound = EventLog.SourceExists("MySource");
}
catch (SecurityException)
{
    sourceFound = false;
}

Another option is to simply elevate your permissions, however, as you where following the tutorial step by step your service would be running under the LocalService account (which again won't have permissions for this particular method). Hence, you will find on the MSDN documentation the solution is to check whether the event source exists in the ServiceInstaller and if it doesn't, create the source in the installer.

回答2:

Are you a local administrator on your machine? If so, put the following line of code at the top of the constructor of your windows service:

System.Diagnostics.Debugger.Break();

When the service starts to run, it'll hit this breakpoint, allowing you to jump into Visual Studio. You can then debug from there until you discover where the exception is occurring.

回答3:

Go get a copy of Process Monitor and watch what happens - you should get the issue showing up as a failure result and you can investigate from there...

edit: To clarify, its a free tool from microsoft (sysinternals) and it does what it says on the tin :)

回答4:

Just a guess: Is your .exe file lying in a network folder? Or is is marked as "downloaded from the Internet"? Because, in that cases, the .NET Framework will assign less permissions to it than when it was directly on a local drive and not marked as downloaded from the internet.