FileSystemWatcher in an AspNetCore 2.1 BackgroundService\IHostedService - asp.net-core

Question

I am trying to use an implementation of the BackgroundService in an AspNet Core 2.1 application. I create a FileSystemWatcher in ExecuteAsync and link the associated events,however, the fsw events are either never fired (unreachable? already disposed?) or its some thing I am doing wrong with this being async or the scope is messed up. I can't seem to figure it out. Following is the relevant code.
public class FSWImpl : BackgroundService
{
private readonly IHostingEnvironment _env;
private readonly ILogger<LiftAndShift> _logger;
private FileSystemWatcher _fsw;
public LiftAndShift(IHostingEnvironment env, ILogger<FSWImpl> logger)
{
_env = env;
_logger = logger;
}
protected override Task ExecuteAsync(CancellationToken stoppingToken)
{
_logger.LogInformation("Creating new FSW");
var path = Path.Combine(_env.ContentRootPath, "WebData");
_fsw = new FileSystemWatcher(path,"*.json");
_fsw.Created += _fsw_Created;
_fsw.Changed += _fsw_Changed;
_fsw.Renamed += _fsw_Renamed;
_fsw.Error += _fsw_Error;
return Task.CompletedTask;
}
private void _fsw_Error(object sender, ErrorEventArgs e) => _logger.LogInformation("File error");
private void _fsw_Renamed(object sender, RenamedEventArgs e) => _logger.LogInformation("File Renamed");
private void _fsw_Changed(object sender, FileSystemEventArgs e) => _logger.LogInformation("File changed");
private void _fsw_Created(object sender, FileSystemEventArgs e) => _logger.LogInformation("File created");
}
I register this service in startup as services.AddHostedService<FSWImpl>();

Answer 1

For enabling FileSystemWatcher, you need to set EnableRaisingEvents as True.
Demo Code:
protected override Task ExecuteAsync(CancellationToken stoppingToken)
{
_logger.LogInformation("Creating new FSW");
var path = Path.Combine(_env.ContentRootPath, "WebData");
_fsw = new FileSystemWatcher(path, "*.json");
_fsw.Created += _fsw_Created;
_fsw.Changed += _fsw_Changed;
_fsw.Renamed += _fsw_Renamed;
_fsw.Error += _fsw_Error;
_fsw.EnableRaisingEvents = true;
return Task.CompletedTask;
}
FileSystemWatcher.cs
//
// Summary:
// Gets or sets a value indicating whether the component is enabled.
//
// Returns:
// true if the component is enabled; otherwise, false. The default is false. If
// you are using the component on a designer in Visual Studio 2005, the default
// is true.
//
// Exceptions:
// T:System.ObjectDisposedException:
// The System.IO.FileSystemWatcher object has been disposed.
//
// T:System.PlatformNotSupportedException:
// The current operating system is not Microsoft Windows NT or later.
//
// T:System.IO.FileNotFoundException:
// The directory specified in System.IO.FileSystemWatcher.Path could not be found.
//
// T:System.ArgumentException:
// System.IO.FileSystemWatcher.Path has not been set or is invalid.
public bool EnableRaisingEvents { get; set; }