（10）根据关键字搜索

问题

当排序和分页和过滤都不够帮用户去找到他们想要的结果时，想一个最好的备选方式是让用户输入（关键字）他们想要什么。

解决方案

用HtmlHelper创建一个新的From和 文本输入框，并且借助LINQ根据用户输入的关键字在之前过滤过的结果里查找。

讨论

和前边的秘方很像，添加一个根据keyword 搜索的功能需要更新 Book/Index view 和 BookController。在View里添加一个新的from和textbox 让用户输入keyword。同时也要确保当用户改变排序规则、过滤、分页时，关键字保持。

下边的代码是对View的更新：

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@model PagedList.IPagedList<MvcApplication.Models.Book> <h2>@MvcApplication4.Resources.Resource1.BookIndexTitle</h2> <p>     @Html.ActionLink("Create New", "Create") </p> <p>     Show:     @if (ViewBag.CurrentFilter != "")     {         @Html.ActionLink("All", "Index", new    {        sortOrder = ViewBag.CurrentSortOrder,        Keyword = ViewBag.CurrentKeyword    })     }     else     {         @:All                 }     &nbsp; | &nbsp;     @if (ViewBag.CurrentFilter != "NewReleases")     {         @Html.ActionLink("New Releases", "Index", new    {        filter = "NewReleases",        sortOrder = ViewBag.CurrentSortOrder,        Keyword = ViewBag.CurrentKeyword    })     }     else     {         @:New Releases                 }     &nbsp; | &nbsp;     @if (ViewBag.CurrentFilter != "ComingSoon")     {         @Html.ActionLink("Coming Soon", "Index", new    {        filter = "ComingSoon",        sortOrder = ViewBag.CurrentSortOrder,        Keyword = ViewBag.CurrentKeyword    })     }     else     {         @:Coming Soon                 } </p> @using (Html.BeginForm()) {     @:Search: @Html.TextBox("Keyword")<input type="submit" value="Search" />   } @Html.Partial("_Paging") <table>     <tr>         <th>             @Html.ActionLink("Title", "Index", new        {            sortOrder = ViewBag.TitleSortParam,            filter = ViewBag.CurrentFilter,            Keyword = ViewBag.CurrentKeyword        })         </th>         <th>             @Html.ActionLink("Isbn", "Index", new        {            sortOrder = ViewBag.IsbnSortParam,            filter = ViewBag.CurrentFilter,            Keyword = ViewBag.CurrentKeyword        })         </th>         <th>             Summary         </th>         <th>             @Html.ActionLink("Author", "Index", new        {            sortOrder = ViewBag.AuthorSortParam,            filter = ViewBag.CurrentFilter,            Keyword = ViewBag.CurrentKeyword        })         </th>         <th>             Thumbnail         </th>         <th>             @Html.ActionLink("Price", "Index", new        {            sortOrder = ViewBag.PriceSortParam,            filter = ViewBag.CurrentFilter,            Keyword = ViewBag.CurrentKeyword        })         </th>         <th>             @Html.ActionLink("Published", "Index", new {     sortOrder = ViewBag.PublishedSortParam,     filter = ViewBag.CurrentFilter,     Keyword = ViewBag.CurrentKeyword })         </th>         <th>         </th>     </tr>     @foreach (var item in Model)     {         <tr>             <td>                 @Html.DisplayFor(modelItem => item.Title)             </td>             <td>                 @Html.DisplayFor(modelItem => item.Isbn)             </td>             <td>                 @Html.DisplayFor(modelItem => item.Summary)             </td>             <td>                 @Html.DisplayFor(modelItem => item.Author)             </td>             <td>                 @Html.DisplayFor(modelItem => item.Thumbnail)             </td>             <td>                 @Html.DisplayFor(modelItem => item.Price)             </td>             <td>                 @Html.DisplayFor(modelItem => item.Published)             </td>             <td>                 @Html.ActionLink("Edit","Edit", new { id = item.ID }) |                 @Html.ActionLink("Details","Details", new { id = item.ID }) |                 @Html.ActionLink("Delete","Delete", new { id = item.ID })             </td>         </tr>     } </table> @Html.Partial("_Paging")

 

最终，BookController 需要被更新，在下边的例子，Index（） action 更新

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using System; using System.Collections.Generic; using System.Data; using System.Data.Entity; using System.Linq; using System.Linq.Dynamic; using System.Web; using System.Web.Mvc; using MvcApplication.Models; using MvcApplication.Utils; using PagedList; namespace MvcApplication.Controllers {     public class BooksController : Controller     {         private BookDBContext db = new BookDBContext();         //         // GET: /Books/         public ViewResult Index(string sortOrder, string filter,string Keyword, int page = 1)         {             #region ViewBag Resources               #endregion             #region ViewBag Sort Params               #endregion             var books = from b in db.Books select b;             #region Keyword Search             if (!String.IsNullOrEmpty(Keyword))             {                 books = books.Where(b =>                 b.Title.ToUpper().Contains(Keyword.ToUpper())                 || b.Author.ToUpper().Contains(                 Keyword.ToUpper()));             }             ViewBag.CurrentKeyword =             String.IsNullOrEmpty(Keyword) ? "" : Keyword;             #endregion             #region Filter Switch               #endregion             int maxRecords = 1;             int currentPage = page - 1;             return View(books.ToPagedList(currentPage,             maxRecords));         }       } }

 

译者：上边代码是以书名和作者名为搜索条件的。你也可以自己扩展。比如根据ISBN：

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books = books.Where(b =>                 b.Title.ToUpper().Contains(Keyword.ToUpper())                 || b.Author.ToUpper().Contains(                 Keyword.ToUpper()||b.ISBN.ToUpper().Contains(                 Keyword.ToUpper()));

 

当然这样做的话查询效率会有问题。我们可以在UI提供一个dropdownlist 让用户去选择根据什么条件去搜索关键字。