public ActionResult EditArticle(EditArticleViewModel editArticleViewModel)
        {
            if (ModelState.IsValid)
            {
                IArticleBLL articleBLL = new ArticleBLL();

                List <Guid> categoryIds = new List <Guid>();
                foreach (string categoryId in editArticleViewModel.CategoryIds)
                {
                    categoryIds.Add(Guid.Parse(categoryId));
                }

                articleBLL.EditArticle(editArticleViewModel.ArticleId, editArticleViewModel.Title, editArticleViewModel.Content, categoryIds.ToArray());
                return(RedirectToAction("ArticleList2"));
            }
            else
            {
                var userId = Guid.Parse(Session["loginUserId"].ToString());
                ViewBag.CategoryIds = new ArticleBLL().GetAllCategories(userId);
                return(View(editArticleViewModel));
            }
        }