Where can I write my log4net log file to under ClickOnce?

Question

When I run my application locally it writes my log4net log to the location I've configured (i.e., <file value="${LOCALAPPDATA}\TEST\Logs\debug.log" />) without a problem. However, when I deploy my application via ClickOnce, the log file is not being written.

I know ClickOnce applications are limited in terms of where they can write to, but I was under the impression that LOCALAPPDATA (e.g., C:\Users\me\AppData\Local) was fair game.

Any ideas?

Answer 1

Isolated Storage.

Answer 2

With ClickOnce, the folder rules are somewhat different than for regular Windows apps. The data folder, where ClickOnce content files are deployed to, is located in c:\Users\me\Local Settings\Apps\2.0\Data. Beneath that folder are a couple of subfolder levels with rather cryptic identifiers.

So the actual data folder for a given ClickOnce app is best retrieved using the ApplicationDeployment class. You should also check the IsNetworkDeployed property to see if you're running in deployed mode:

if (ApplicationDeployment.IsNetworkDeployed)
{
    var dataDirectory = ApplicationDeployment.CurrentDeployment.DataDirectory;
    ...
}

Since the DataDirectory is decided by ClickOnce there is no way you can hardcode that path into your log4net config. My suggestion would be to modify the file paths programmaticaly at application startup.

foreach(var appender in LogManager.GetRepository().GetAppenders())
{
    var fileAppender = appender as FileAppender;
    if (fileAppender != null)
    {
        fileAppender.File = 
            fileAppender.File.Replace("${LOCALAPPDATA}", dataDirectory);
        fileAppender.ActivateOptions();
    }
}