c# metro ETW - some events are not logged

Question

I have a C#/XAML application and I use ETW to log events to flat file.

9/10 times the StorageFile is not set and my event is not logged.

Constructor:

public AppEventSource(string logFileName)
{
    this._logFileName = logFileName;
    AssignLocalFile();
}

private async void AssignLocalFile()
{
    _storageFile = await ApplicationData.Current.LocalFolder.CreateFileAsync(
        _logFileName), 
        CreationCollisonOption.OpenIfExists);
}

private async void WriteToFile(IEnumerable<string> lines)
{
    await _semaphore.WaitAsync();

    await Task.Run(async() =>
    {
        await FileIO.AppendLinesAsync(_storageFile, lines);
        _semaphore.Release();
    });
}

protected override void OnEventWritten(EventWrittenEventArgs eventData)
{
    if(_storageFile == null) return;
    List<string> lines = new List<string>();
    // formatting stuff....
    WriteToFile(lines);
}

The files are created always but 9/10 times are not written to.

For reference here is how I set up the listener:

EventListener informationListener = new AppEventsListener("Information");
informationListener.EnableEvents(AppEventsSource.Log, EventLevel.Informational);

And sample log:

AppEventsSource.Log.Info("log entry #1");

You should avoid `async void` (use `async Task` instead). Are you getting any exceptions? — Stephen Cleary, Nov 12 '13 at 12:45
No exceptions, just when I step through the code the AssignLocalFile always returns null, but the log file is created. — andrewb, Nov 12 '13 at 20:58

c# metro ETW - some events are not logged

0 Answers0