ASP.NET MVC C搜索帮助

我在homecontroller.cs中有以下代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Mvc.Ajax;
using MyApplication.Models;

namespace MyApplication.Controllers
{
    public class HomeController : Controller
    {
        private NewsDBEntities _db = new NewsDBEntities();

        //
        // GET: /Home/

        public ActionResult Index()
        {

            return View(_db.ArticleSet.ToList());

        }

        //
        // GET: /Home/Details/5

        public ActionResult Details(int id)
        {
            //return View();

            var ArticleToView = (from m in _db.ArticleSet

                               where m.storyId == id

                               select m).First();

            return View(ArticleToView);
        }



        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Index(String query)
        {

            var ArticleQuery = (from m in _db.ArticleSet

                                where m.headline.Contains(query)

                                select m).First();

            return View(ArticleQuery);

            //return RedirectToAction("Search");

        }

    }
}

在home/index.aspx下的视图文件夹中,我有一个简单的搜索表单,如下所示:

    <% using (Html.BeginForm()) {%>

        <fieldset>
            <legend>Search</legend>
            <p>
                <label for="query">Keywords:</label>
                <%= Html.TextBox("query") %>
            </p>
            <p>
                <input type="submit" value="Search" />
            </p>
        </fieldset>

    <% } %>

其想法是,当用户提交此表单时,将使用查询文本框的内容,然后对照来自我的数据库的文章标题进行检查,索引视图将不显示所有文章,而只显示与用户键入的查询匹配的文章。

当我提交表单时,我得到以下错误:

The model item passed into the dictionary is of type 'MyApplication.Models.Article' but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[MyApplication.Models.Article]'. 

我在这里做错了什么?据我所知,代码是好的。