使用JQuery自动完成插件Auto Complete详解
问题
当你查找一些特殊的东西,当你输入准确的词时,找到它可能是困难的(或者很耗时)。在输入的时候展示出结果(自动完成),使查找变得更简单。
解决方案
使用jquery自动完成插件,更新现有图书列表页面上的搜索,当用户键入的时候立即显示结果。
讨论
自动完成插件是不会象jquery基本库一样自动包含在mvc项目中的,所以需要做的第一件事就是的是下载插件
访问http://jquery.com/。两个主要的文件是必需的:javascript文件和css文件。把新下载的javascript文件放到你mvc应用程序的script 文件夹下。css文件可以直接添加到您的content目录。
这个配方也将介绍在view中使用 rendering sections。在shared文件夹下layout中自动添加了2个javascript文件和1个css文件。这些是ajax和不唐突的ajax和网站主css文件。每次加载的内容越多,页面视图加载越慢。与其在每个页面都去包含可能不必要的javascript和css 文件,不如在layout中添加一个新的rendersection()。这允许特别的view在<head>标签去加载特别的javascript或css,但不是每页都添加他们。
下边是一个更新后的views/shared/_layout.cshtml,他使用了一个新的rendersection()。
<!doctype html> <html> <head> <title>_mobile</title> <link href="@url.content(" rel="external nofollow" rel="external nofollow" ~/content/site.css")" rel="stylesheet" type="text/css" /> <script src="@url.content("~/scripts/jquery-1.6.2.min.js")" type="text/javascript"></script> <script type="text/javascript"> $(document).ready(function () { if (window.innerwidth <= 480) { $("link[rel=stylesheet]").attr({ href: "@url.content("~/content/jquery.mobile-1.0b1.min.css")" }); } }); </script> @rendersection("javascriptandcss", required: false) </head> <body> <div class="page" data-role="page"> <div id="header" data-role="header"> <div id="title"> <h1>my mvc application</h1> </div> <div id="logindisplay" class="ui-bar"> @html.partial("_logonpartial") [ @html.actionlink("english", "changelanguage", "home", new { language = "en" }, null) ] [ @html.actionlink("français", "changelanguage", "home", new { language = "fr" }, null) ] </div> <div id="menucontainer" class="ui-bar"> <ul id="menu"> <li>@html.actionlink("home", "index", "home", null, new dictionary<string, object> {{ "data-role", "button" }})</li> <li>@html.actionlink("about", "about", "home", null, new dictionary<string, object> { { "data-role", "button" }})</li> </ul> </div> </div> <div id="main" data-role="content"> @renderbody() </div> <div id="footer" data-role="footer"> </div> </div> </body> </html>
主要的css文件和核心的jquery文件被留下来了,因为css在每个也都需要,并且绝大多数网页也需要jquery。然而新的jquery文件和不唐突的ajax不是每个页面都需要的。
现在,有两种方式使用autocomplete 插件:
1.在javascript中设置要搜索的数据。
2.当用户输入时通过ajax检索。
在我使用这个插件的经验看来,我发现使用解决方案1时自动完成更快。因为它并不需要每次从数据库中请求数据。然而,使用这种解决方案的限制:只有这么多字符,可传递到function中,大量的javascript可能会导致用户的计算机上页面加载缓慢。经过一些试验和错误,我已经确定神奇的数字是大约40,000个结果。如果结果数量超过此,最好使用选项2;否则,始终坚持,因为搜索选项1是瞬时,而不是有轻微的延迟。
在这个例子中,将搜索书籍,我们没有超过40000,所以将使用选项1。bookscontroller现在必须更新,以设置viewbag为book title。自动完成功能需要支持一个javascript数组的支持,所以书将管道(|)分开。然后在view中,书将被转换到一个数组,使用javascript的split()函数。当用户完成键入他们的结果,他们应该有选择完全匹配标题,因此这个函数将被更新。如果只有1本书返回并且用户执行了搜索,它会自动重定向到本书详细介绍页面。
我们要在bookcontroller 中更新index action 并添加一个私有方法名为:formatbooksforautocomplete。
代码如下:
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/ [outputcache(duration = int32.maxvalue, sqldependency = "mvcapplication.models.bookdbcontext:books", varybyparam = "sortorder;filter;page")] public actionresult index(string sortorder, string filter, string keyword, int page = 1) { #region viewbag resources viewbag.title = resources.resource1.bookindextitle; viewbag.createlink = resources.resource1.createlink; viewbag.titledisplay = resources.resource1.titledisplay; viewbag.isbndisplay = resources.resource1.isbndisplay; viewbag.summarydisplay = resources.resource1.summarydisplay; viewbag.authordisplay = resources.resource1.authordisplay; viewbag.thumbnaildisplay = resources.resource1.thumbnaildisplay; viewbag.pricedisplay = resources.resource1.pricedisplay; viewbag.publisheddisplay = resources.resource1.publisheddisplay; viewbag.editlink = resources.resource1.editlink; viewbag.detailslink = resources.resource1.detailslink; viewbag.deletelink = resources.resource1.deletelink; #endregion #region viewbag sort params viewbag.titlesortparam = (sortorder == "title") ? "title desc" : "title"; viewbag.isbnsortparam = (sortorder == "isbn") ? "isbn desc" : "isbn"; viewbag.authorsortparam = (sortorder == "author") ? "author desc" : "author"; viewbag.pricesortparam = (sortorder == "price") ? "price desc" : "price"; viewbag.publishedsortparam = (string.isnullorempty(sortorder)) ? "published desc" : ""; // default the sort order if (string.isnullorempty(sortorder)) { sortorder = "published desc"; } viewbag.currentsortorder = sortorder; #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())); // should we redirect because of only one result? if (books.count() == 1) { book book = books.first(); return redirecttoaction("details", new { id = book.id }); } } viewbag.currentkeyword = string.isnullorempty(keyword) ? "" : keyword; #endregion #region filter switch switch (filter) { case "newreleases": var startdate = datetime.today.adddays(-14); books = books.where(b => b.published <= datetime.today.date && b.published >= startdate ); break; case "comingsoon": books = books.where(b => b.published > datetime.today.date); break; default: // no filter needed break; } viewbag.currentfilter = string.isnullorempty(filter) ? "" : filter; #endregion books = books.orderby(sortorder); int maxrecords = 1; int currentpage = page - 1; // get all book titles viewbag.booktitles = formatbooksforautocomplete(); return view(books.topagedlist(currentpage, maxrecords)); } private string formatbooksforautocomplete() { string booktitles = string.empty; var books = from b in db.books select b; foreach (book book in books) { if (booktitles.length > 0) { booktitles += "|"; } booktitles += book.title; } return booktitles; } // // get: /books/details/5 public actionresult details(int id = 0, string booktitle = "") { book book = db.books.find(id); return view(book); } // // get: /books/create public actionresult create() { return view(); } // // post: /books/create [httppost] public actionresult create(book book, httppostedfilebase file) { if (modelstate.isvalid) { // upload our file book.thumbnail = fileupload.uploadfile(file); db.books.add(book); db.savechanges(); return redirecttoaction("index"); } return view(book); } // // get: /books/edit/5 public actionresult edit(int id) { book book = db.books.find(id); return view(book); } // // post: /books/edit/5 [httppost] public actionresult edit(book book, httppostedfilebase file) { if (modelstate.isvalid) { // delete old file fileupload.deletefile(book.thumbnail); // upload our file book.thumbnail = fileupload.uploadfile(file); db.entry(book).state = entitystate.modified; db.savechanges(); return redirecttoaction("index"); } return view(book); } // // get: /books/delete/5 public actionresult delete(int id) { book book = db.books.find(id); return view(book); } // // post: /books/delete/5 [httppost, actionname("delete")] public actionresult deleteconfirmed(int id) { book book = db.books.find(id); // delete old file fileupload.deletefile(book.thumbnail); db.books.remove(book); db.savechanges(); return redirecttoaction("index"); } protected override void dispose(bool disposing) { db.dispose(); base.dispose(disposing); } } }
最后book/index view需要更新去初始化jquery的自动完成。要做的第一件事是使用@节标记,包括必要的javascript和css文件。接下来,以前创建的搜索文本框更新设置一个键的idwordsearch。
最后,javascript代码添加在视图的底部去在搜索文本框上建立自动完成功能。此javascript是有意添加在view的底部,以确保完全呈现给用户,因为在用户的电脑上建立数据是一项工作,javascript处理可能会“堵塞”页面加载。
(译者:先呈现数据再执行javascript,js不是像传统那样放在head标签里)
这取决于结果的数量。代码如下:
@model pagedlist.ipagedlist<mvcapplication.models.book> @if (isajax) { layout = null; } @section javascriptandcss { <link rel="stylesheet" href="@url.content(" rel="external nofollow" rel="external nofollow" ~/content/jquery.autocomplete.css")" type="text/css" /> <script type="text/javascript" src="@url.content("~/scripts/jquery.autocomplete.js")"></script> <script src="@url.content("~/scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> } <h2>@mvcapplication4.resources.resource1.bookindextitle</h2> <p> @html.actionlink("create new", "create") </p> <p> show: @if (viewbag.currentfilter != "") { @ajax.actionlink("all", "index", new { sortorder = viewbag.currentsortorder, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) } else { @:all } | @if (viewbag.currentfilter != "newreleases") { @ajax.actionlink("new releases", "index", new { filter = "newreleases", sortorder = viewbag.currentsortorder, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) } else { @:new releases } | @if (viewbag.currentfilter != "comingsoon") { @ajax.actionlink("coming soon", "index", new { filter = "comingsoon", sortorder = viewbag.currentsortorder, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) } else { @:coming soon } </p> @using (html.beginform()) { @:search: @html.textbox("keyword", (string)viewbag.currentkeyword, new { id = "keywordsearch" }) <input type="submit" value="search" /> } @html.partial("_paging") <table> <tr> <th> @ajax.actionlink("title", "index", new { sortorder = viewbag.titlesortparam, filter = viewbag.currentfilter, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) </th> <th> @ajax.actionlink("isbn", "index", new { sortorder = viewbag.isbnsortparam, filter = viewbag.currentfilter, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) </th> <th> summary </th> <th> @ajax.actionlink("author", "index", new { sortorder = viewbag.authorsortparam, filter = viewbag.currentfilter, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) </th> <th> thumbnail </th> <th> @ajax.actionlink("price", "index", new { sortorder = viewbag.pricesortparam, filter = viewbag.currentfilter, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) </th> <th> @ajax.actionlink("published", "index", new { sortorder = viewbag.publishedsortparam, filter = viewbag.currentfilter, keyword = viewbag.currentkeyword }, new ajaxoptions { updatetargetid = "main" }) </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") <script type="text/javascript"> $(document).ready(function () { var data = "@viewbag.booktitles".split("|"); $("#keywordsearch").autocomplete(data); }); </script>
为了实施选项2,一个ajax搜索,而不是传递数据数组到自动完成函数,您可以传递一个url。url将需要接受查询字符串变量:q。这包含用户输入的搜索值。这将用于执行书本上包含部分匹配的搜索,并返回以分隔符分隔的字符串。jquery文档中含有较多的这样的成品例子,也有其他的例子,去更新的输出结果(可能包括书的封面的缩略图)。
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。