void BackgroundUpload(object sender, DoWorkEventArgs e)
{
var book = (Book.Book) e.Argument;
var languages = _languagesFlow.Controls.Cast<CheckBox>().Where(b => b.Checked).Select(b => b.Tag).Cast<string>().ToArray();
var result = _bookTransferrer.FullUpload(book, _progressBox, _parentView, languages, out _parseId);
e.Result = result;
}