Question

I have built a Windows Service and for some reason, when I start the service it starts up and then shuts right back down. I’ve tried googling why this is happening. Nothing is appearing in any system logs. Here is my Start/Stop code for the service. I would expect that since I have created a File Listener that it should stay running. What am I missing?

#region Declarations
private List<string> _keys = new List<string>();
private FileSystemWatcher _watcher;
private BackgroundWorker _worker;
static private bool _isBusy = false;
#endregion

#region Constructor
public FeedListener()
{
    InitializeComponent();
}
#endregion

#region Start/Stop
protected override void OnStart(string[] args)
{
    _keys.AddRange(new string[] { "csv", "xml", "zip", "rivx" });

    _worker = new BackgroundWorker();
    _worker.WorkerReportsProgress = true;
    _worker.WorkerSupportsCancellation = true;
    _worker.DoWork += new DoWorkEventHandler(BackgroundWorkerDoWork);
    _worker.ProgressChanged += new ProgressChangedEventHandler(BackgroundWorkerProgressChanged);
    _worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(BackgroundWorkerRunWorkerCompleted);

    _watcher = new FileSystemWatcher(AppSettings.Default.FTPRootPath, "*.*");
    _watcher.IncludeSubdirectories = true;
    _watcher.NotifyFilter = sysIO.NotifyFilters.DirectoryName | sysIO.NotifyFilters.FileName | sysIO.NotifyFilters.LastAccess | sysIO.NotifyFilters.CreationTime | sysIO.NotifyFilters.LastWrite;
    _watcher.Created += new sysIO.FileSystemEventHandler(fileCreatedOrChanged);
    _watcher.Changed += new sysIO.FileSystemEventHandler(fileCreatedOrChanged);
    _watcher.EnableRaisingEvents = true;

    TouchFiles();
}
protected override void OnStop()
{
    _watcher.Dispose();
    _watcher = null;
    _worker.Dispose();
    _worker = null;
}
#endregion

#region Event Handlers
void fileCreatedOrChanged(object sender, sysIO.FileSystemEventArgs e)
{
    DTO.BackgroundWorkerEventArgs eventArgs = new DTO.BackgroundWorkerEventArgs();
    sysIO.WatcherChangeTypes myType = e.ChangeType;

    bool isValid = false;
    foreach (string key in _keys)
    {
        if (Path.GetExtension(e.FullPath).Replace(".", "").Equals(key, StringComparison.CurrentCultureIgnoreCase))
            isValid = true;
    }
    if (isValid)
    {
        try
        {
            eventArgs.PathAndFile = e.FullPath;
            eventArgs.Key = Path.GetExtension(e.FullPath).ToLower().Replace(".", "");
            eventArgs.FileName = Path.GetFileName(e.FullPath);
            eventArgs.Path = Path.GetDirectoryName(e.FullPath);
            eventArgs.UserName = Path.GetDirectoryName(e.FullPath).Replace(AppSettings.Default.FTPRootPath, "").Replace("\\", "");

            FileInfo fileInfo = new FileInfo(eventArgs.PathAndFile);

            // 1st attempt at stalling for the file lock due to slow write speeds...
            while (IsFileLocked(fileInfo)) { /* nop */ }

            // Wait until the thread is not busy...
            //while (_worker.IsBusy) { /* nop */ }
            while (_isBusy) { /* nop */ }

            // Now, spin up a new thread and do the work on the file, based on file type...
            _worker.RunWorkerAsync(eventArgs);  // goes to BackgroundWorkerDoWork(object sender, DoWorkEventArgs e) //
        }
        catch (Exception ex)
        {
            string m = ex.Message;
        }
    }
}
void BackgroundWorkerDoWork(object sender, DoWorkEventArgs e)
{
    DTO.BackgroundWorkerEventArgs eventArgs = (DTO.BackgroundWorkerEventArgs)e.Argument;
    RivWorks.FeedHandler.Handler handler = new RivWorks.FeedHandler.Handler();
    _isBusy = true;

    try
    {
        if (eventArgs.Key.Equals("csv", StringComparison.CurrentCultureIgnoreCase))
        {
            handler.ImportCSV(ref eventArgs);
        }
        if (eventArgs.Key.Equals("zip", StringComparison.CurrentCultureIgnoreCase))
        {
            handler.UnZip(ref eventArgs);
            handler.ImportCSV(ref eventArgs);
        }
    }
    catch (Exception ex)
    {
        string m = ex.Message;
        _worker.ReportProgress(0);
    }
    finally
    {
        _isBusy = false;
        _worker.ReportProgress(100);
        if (_worker.CancellationPending)
        {
            e.Cancel = true;
        }
    }
}
void BackgroundWorkerProgressChanged(object sender, ProgressChangedEventArgs e)
{
}
void BackgroundWorkerRunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        Console.WriteLine("Cancelled.");
    }
    else if (e.Error != null)
    {
        Console.WriteLine(e.Error.Message);
    }
    else
    {
        Console.WriteLine("Successfully completed.");
    }

    TouchFiles();
}
#endregion

Answer 1

I posted an answer in your other, related post… I believe the issue is that you’re firing multiple RunWorkAsync calls on the same BackgroundWorker, and this is probably crashing the service.

Also, you’re using an _isBusy flag in the context of multi-threaded background workers… you need to use a multi-threaded locking system, such as a Mutex (though I still say that defeats the point of running BackgroundWorkers asynchronously).

Check the answer here: C# based Windows Service – Tries to do JIT Debugging in production