asp.net mvc中的搜索方法或过滤器是什么

Question

asp.net mvc中的搜索方法或过滤器是什么在索引页的多列中

 public ActionResult Index(string searchString)
    {
        var books = from b in _context.books select b;

        if (!string.IsNullOrWhiteSpace(searchString))
        {
            books = books.Where(b => b.txt1.Contains(searchString));
        }


        return View(books.ToList());
    }