/// <summary>
 /// Recarga el historial de archivos encolados para transferencias y/o descargas
 /// </summary>
 private void refreshList(FileItem fileItem)
 {
     bool exist = false;
     foreach (TreeNode node in treeView.Nodes)
     {
         String filehandlerID = (String)node.Tag;
         if (filehandlerID.Equals(fileItem.FileHandlerId))
         {
             node.Text = fileItem.ToString();
             exist = true;
             break;
         }
     }
     if (!exist)
     {
         TreeNode fileNode = new TreeNode(fileItem.ToString());
         fileNode.ImageIndex = 0;
         fileNode.SelectedImageIndex = 0;
         fileNode.Tag = fileItem.FileHandlerId;
         treeView.Nodes.Add(fileNode);
     }
 }