public IActionResult AddBlog(String title, String content, Guid categoryId = default(Guid), Guid tagId = default(Guid)) { if (String.IsNullOrEmpty(title)) { throw new ArgumentNullException($"{nameof(title)}"); } if (String.IsNullOrEmpty(content)) { throw new ArgumentNullException($"{nameof(content)}"); } if (categoryId == Guid.Empty) { throw new ArgumentNullException($"{nameof(categoryId)}"); } if (tagId == Guid.Empty) { throw new ArgumentNullException($"{nameof(tagId)}"); } _blogService.AddNewBlog(title, content, categoryId, tagId); return(Json(new { })); }