private void btnAdd_Click(object sender, RoutedEventArgs e)
        {
            string url = txtUrl.Text;

            if (Util.IsYoutubeVideoUrl(url))
            {
                new YoutubeDownloadWnd(url, this).ShowDialog();
            }
            else
            {
                try {
                    DownloadTask dl = new DownloadTask(url).Initialize();
                    DlQueue.Add(dl);

                    if (chkStartNow.IsChecked.HasValue && chkStartNow.IsChecked.Value)
                    {
                        string path = getSaveLocation(dl);

                        if (path != null)
                        {
                            dl.DownloadAsync(path);
                        }
                    }
                }
                catch (Exception ex) {
                    MessageBox.Show(ex.Message, "Oops! An error occured.");
                }
            }
        }