public async Task <IActionResult> Edit(int id, [Bind("ThemeId,AuthorId")] ThemeAuthor themeAuthor)
        {
            if (id != themeAuthor.ThemeId)
            {
                return(NotFound());
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(themeAuthor);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!ThemeAuthorExists(themeAuthor.ThemeId))
                    {
                        return(NotFound());
                    }
                    else
                    {
                        throw;
                    }
                }
                return(RedirectToAction(nameof(Index)));
            }
            ViewData["AuthorId"] = new SelectList(_context.Author, "Id", "LastName", themeAuthor.AuthorId);
            ViewData["ThemeId"]  = new SelectList(_context.Theme, "Id", "Name", themeAuthor.ThemeId);
            return(View(themeAuthor));
        }
        public async Task <IActionResult> Create([Bind("ThemeId,AuthorId")] ThemeAuthor themeAuthor)
        {
            if (ModelState.IsValid)
            {
                _context.Add(themeAuthor);
                await _context.SaveChangesAsync();

                return(RedirectToAction(nameof(Index)));
            }
            ViewData["AuthorId"] = new SelectList(_context.Author, "Id", "LastName", themeAuthor.AuthorId);
            ViewData["ThemeId"]  = new SelectList(_context.Theme, "Id", "Name", themeAuthor.ThemeId);
            return(View(themeAuthor));
        }