>>There's a Window's event that fires when a new file is created. I'm not sure if it fires on first creation or when it's closed. Binding to that event is better than watching a folder for a new file.
>
>This is from a robot application that is executing a process on the file. So, there is an incoming and once completed, the robot needs to process it. The robot runs every minute. But, I need to make sure it doesn't grab a file if the transfer is still in progress. For now, I have put a verification to make sure the timestamp of the file is at least 20 seconds from Date.Now. I am not sure I can have a bind from the robot to an event in such infrastucture.


I am writing something very similar right now, I am ftping 75Mb files and when they are ready I need to parse them, so when I detect a new file with the FileSystemWatcher class I wait until the file is ready by trying to open it exclusively, this is my code:

        protected void WaitUntilFileIsReady(System.String fileName)
        {
            if (_eventLogger != null)
            {
                _eventLogger.LogEvent(string.Format("Waiting for file availability ({0} current size: {1} bytes", fileName, GetFileSize(fileName).ToString(System.Globalization.CultureInfo.InvariantCulture)), EventTypes.Wait);
                while (!IsFileReady(fileName))
                    System.Threading.Thread.Sleep(50);
                _eventLogger.LogEvent(string.Format("The file {0} is available! ({1}) bytes", fileName, GetFileSize(fileName).ToString(System.Globalization.CultureInfo.InvariantCulture)), EventTypes.Available);
            }
        }

        protected static bool IsFileReady(System.String fileName)
        {
            // If the file can be opened for exclusive access it means that the file
            // is no longer locked by another process.
            try
            {
                using (System.IO.FileStream inputStream = System.IO.File.Open(fileName, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.None))
                {
                    return (inputStream.Length >= 0); 
                }
            }
            catch (System.Exception)
            {
                return false;
            }
        }

You can ignore the _eventLogger, as that is something I use to write into Windows Event Logger (and a SQL DB) to track activity.