C# Error แบบนี้ แก้ยังไงครับ (จะเช็คการสิ้นสุดการทำงานของ youtube_dl.exe ครับ)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;

using NLog;
using TorServices;

using Microsoft.WindowsAPICodePack.Shell;
using Microsoft.WindowsAPICodePack.Shell.PropertySystem;
namespace PlaylistDownloader
{
    //https://github.com/bertyhell/PlaylistDownloader/blob/master/PlaylistDownloader/PlaylistDownloader/Downloader.cs

    public class Downloader : BackgroundWorker
    {

        private readonly List<PlaylistItem> _playlist;
        private readonly RunSettings _runSettings;

        private int _progress;
        private int _totalSongs;
        private int _completeSongs;
        private CancellationTokenSource _cts;
        private static Logger logger = LogManager.GetCurrentClassLogger();
        public double progressValue = 0d;
        private bool ConverttoMP3;
        public Downloader(RunSettings settings, ICollection<PlaylistItem> playlist,bool converttomp3)
        {
            _playlist = playlist.ToList<PlaylistItem>();
            _totalSongs = _playlist.Count;

            _cts = new CancellationTokenSource();

            _runSettings = settings;
            ConverttoMP3 = converttomp3;
        }
        int itemIndex = 0;
        protected override void OnDoWork(DoWorkEventArgs args)
        {
            _progress = 0;

          //  LimitedConcurrencyLevelTaskScheduler scheduler = new LimitedConcurrencyLevelTaskScheduler(1);
         //   var factory = new TaskFactory(scheduler);
           // var tasks = new List<Task>();

            _playlist.ForEach(plst =>
            {
            DownloadPlaylistItem(plst);
            // tasks.Add(factory.StartNew(() => DownloadPlaylistItem(plst)));
        });

          //  Task.WaitAll(tasks.ToArray());


        }
        //https://markheath.net/post/how-to-get-media-file-duration-in-c
        TimeSpan GetDuration(string filePath)
        {
            using (var shell = ShellObject.FromParsingName(filePath))
            {
                IShellProperty prop = shell.Properties.System.Media.Duration;
                var t = (ulong)prop.ValueAsObject;
                return TimeSpan.FromTicks((long)t);
            }
        }
        public void DownloadPlaylistItem(PlaylistItem item)
        {
            string destinationFilePathWithoutExtension = null;
           // string tempFilePathWithoutExtension = null;

            item.DownloadProgress = 5;
            if (!string.IsNullOrWhiteSpace(item.FileName))
            {
               // tempFilePathWithoutExtension = Path.Combine(_runSettings.FolTemp, item.FileName.MakeValidFileName());
                destinationFilePathWithoutExtension = Path.Combine(_runSettings.SongsFolder, item.FileName.MakeValidFileName()) ;
                item.DownloadProgress = 10;
                if (!File.Exists(destinationFilePathWithoutExtension + ".mp4"))
                {
                    StartProcessyoutube_dl(item,  destinationFilePathWithoutExtension, ParseYoutubeDlProgress);
                }
                else
                {
                    Finish(item, destinationFilePathWithoutExtension);
                }
            }
            else
            {
                Finish(item, destinationFilePathWithoutExtension);

            }


        }
        
        private string StartProcessyoutube_dl(PlaylistItem item, string desFile, Action<string, PlaylistItem> parseProgressFunc)
        {
            string executablePath = _runSettings.YoutubeDlPath;
            string destinationFilePathWithoutExtension = desFile;
         
            var promise = new TaskCompletionSource<string>();

            string arguments = string.Format( " --audio-quality 0 --no-part --output \"{0}\" {1}",  destinationFilePathWithoutExtension + ".mp4", item.Link);

            logger.Info("[RUN CMD] " + executablePath + arguments);
            string _filename = executablePath;
            Process process = new Process
            {
                StartInfo =
              {
                  FileName = executablePath,
                  Arguments = arguments,
                  CreateNoWindow = !_runSettings.IsDebug,
                  WindowStyle = _runSettings.IsDebug ? ProcessWindowStyle.Normal : ProcessWindowStyle.Hidden,
                  RedirectStandardOutput = true,
                  RedirectStandardError = true,
                  UseShellExecute = false

              },
                EnableRaisingEvents = true
            };
            // --audio-quality 5 --extract-audio --audio-format mp3  -o "c:\Users\Julian\Music\PlaylistDownloader\\%(title)s.%(ext)s" https://www.youtube.com/watch?v=mDuElaL1dU0

            process.OutputDataReceived += (object sender, DataReceivedEventArgs e) =>
            {
                string consoleLine = e.Data;
                if (!string.IsNullOrWhiteSpace(consoleLine))
                {
                    logger.Info(consoleLine);
                    parseProgressFunc(consoleLine, item);
                }

                if (CancellationPending)
                {
                    logger.Info("Canceling process because of user: " + executablePath);
                    process.Close();
                    promise.SetResult(null);
                }
            };

            process.ErrorDataReceived += (object sender, DataReceivedEventArgs e) =>
            {
                string consoleLine = e.Data;

                if (!string.IsNullOrWhiteSpace(consoleLine))
                {
                    logger.Info("Error: " + consoleLine);
                    parseProgressFunc(consoleLine, item);
                }

                if (CancellationPending)
                {
                    logger.Info("Canceling process because of user: " + executablePath);
                    process.Close();
                    promise.SetResult(null);
                }
                // Finish(item, tempFilePathWithoutExtension);
            };

            process.Exited += new EventHandler((object sender, EventArgs e) =>
            {

                process.Dispose();
                logger.Info("Closing process");

                promise.SetResult(null);

                if (File.Exists(destinationFilePathWithoutExtension + ".mp4"))
                {
                    if (new FileInfo(destinationFilePathWithoutExtension + ".mp4").Length > 0)
                    {
                        Thread.Sleep(1000);

                        if (ConverttoMP3)
                        {
                            if (!System.IO.File.Exists(destinationFilePathWithoutExtension + ".mp3"))
                            {
                                StartProcessffmpeg(item, destinationFilePathWithoutExtension);

                            }
                            else
                            {
                                Finish(item, destinationFilePathWithoutExtension);
                            }
                            
                        }
                        else
                        {
                            Finish(item, destinationFilePathWithoutExtension);
                        }

                        //Finish(item, destinationFilePathWithoutExtension);
                        // 
                    }
                }



            });

            process.Start();


            process.BeginOutputReadLine();
            process.BeginErrorReadLine();

           /* do
             {
                 Thread.Sleep(1000);

             } while (!File.Exists(destinationFilePathWithoutExtension + ".mp4") || new FileInfo(destinationFilePathWithoutExtension + ".mp4").Length < 20000);
           */

                do
                {
                    Thread.Sleep(1000);
  
                } while ( GetDuration(destinationFilePathWithoutExtension + ".mp4").TotalMinutes <= 0);

            
            

                   
                    if (ConverttoMP3)
                    {
                        if (!System.IO.File.Exists(destinationFilePathWithoutExtension + ".mp3"))
                        {
                            StartProcessffmpeg(item, destinationFilePathWithoutExtension);

                        }
                        else
                        {
                            Finish(item, destinationFilePathWithoutExtension);
                        }
                    }
                    else
                    {
                        Finish(item, destinationFilePathWithoutExtension);
                    }

         
          
            return promise.Task.Result;
        }

        private string StartProcessffmpeg(PlaylistItem item,  string desFile)
        {
            string executablePath = _runSettings.FfmpegPath;
            string destinationFilePathWithoutExtension = desFile;
          
            var promise = new TaskCompletionSource<string>();

       
            string arguments = string.Format(" -i \"{0}\" -b:a 192K -vn \"{1}\"", destinationFilePathWithoutExtension + ".mp4", destinationFilePathWithoutExtension + ".mp3");

            logger.Info("[RUN CMD] " + executablePath + arguments);
            string _filename = executablePath;
            Process process = new Process
            {
                StartInfo =
              {
                  FileName = executablePath,
                  Arguments = arguments,
                  CreateNoWindow = !_runSettings.IsDebug,
                  WindowStyle = _runSettings.IsDebug ? ProcessWindowStyle.Normal : ProcessWindowStyle.Hidden,
                  RedirectStandardOutput = true,
                  RedirectStandardError = true,
                  UseShellExecute = false

              },
                EnableRaisingEvents = true
            };

      
            process.Exited += new EventHandler((object sender, EventArgs e) =>
            {

                process.Dispose();
                logger.Info("Closing process");
                promise.SetResult(null);

                  Finish(item, destinationFilePathWithoutExtension);

              
            });

            process.Start();
            process.BeginOutputReadLine();
            process.BeginErrorReadLine();

            do
            {
                Thread.Sleep(1000);

            } while (GetDuration(destinationFilePathWithoutExtension + ".mp3").TotalMinutes <= 0);//new FileInfo(destinationFilePathWithoutExtension + ".mp3").Length < 1000

          
                    Thread.Sleep(3000);
                File.Delete(destinationFilePathWithoutExtension + ".mp4");
            Thread.Sleep(2000);
            Finish(item, destinationFilePathWithoutExtension);

            

                return promise.Task.Result;
        }

        private void ParseYoutubeDlProgress(string consoleLine, PlaylistItem item)
        {
            // [download]   0.0% of 4.66MiB at 336.14KiB/s ETA 00:14
            Regex extractDownloadProgress = new Regex(@"\[download\][\s]*([0-9\.]+)%");
            Match match = extractDownloadProgress.Match(consoleLine);
            if (match.Length > 0 && match.Groups.Count >= 2)
            {
                if (double.TryParse(match.Groups[1].Value, System.Globalization.NumberStyles.Float, System.Globalization.CultureInfo.InvariantCulture, out double downloadProgress))
                {
                    logger.Info("[download + convert progress] " + downloadProgress);
                    if (downloadProgress > 100)//|| _progress > 100
                    {

                        Debugger.Break();
                    }
                    item.DownloadProgress = (double)(10.0 + downloadProgress / 100 * 60);

                    OnProgressChanged(new ProgressChangedEventArgs(_progress * 100 / _totalSongs, null));

                }
            }
        }


        public void Finish(PlaylistItem item,string destinationFile)
        {
            item.DownloadProgress = 100;
            itemIndex++;
            _progress++;
            progressValue = Convert.ToDouble(((double)_progress * 100d / (double)_totalSongs).ToString("N2"));
            OnProgressChanged(new ProgressChangedEventArgs(_progress * 100 / _totalSongs, null));
            try
            {
              

                if (itemIndex < _playlist.Count)
                    DownloadPlaylistItem(_playlist[itemIndex]);


            }
            catch { }


        }
        internal void Abort()
        {
            if (_cts != null)
            {
                _cts.Cancel();
                _cts = null;
            }
            CancelAsync();
        }


    }
}