在Asp.net MVC中,我们能非常方便的使用Ajax。这篇文章将介绍三种Ajax使用的方式,分别为原始的Ajax调用、Jquery、Ajax Helper。分别采用这三种方式结合asp.net mvc去实现一个史上最简单的留言板。
首先看一下原始的Ajax的调用的:
定义CommentController,代码如下:
public class CommentController : Controller{ private IList < string > _comments = new List < string > (); public ActionResult Index() { return View(); } public void AddCommentServer() { string comment = Request[ " comment " ].ToUpper(); _comments.Add( " <li> " + comment + " </li> " ); Response.ContentType = " text/html " ; Response.Write( string .Join( " \n " , _comments.ToArray())); }} 在Asp.net MVC中添加一个custom_ajax.js,加入下面使用ajax的脚本代码,调用AddCommentServer方法。
function getXmlHttpRequest() { var xhr; // check for IE implementation(s) if ( typeof ActiveXObject != ' undefined ' ) { try { xhr = new ActiveXObject( " Msxml2.XMLHTTP " ); } catch (e) { xhr = new ActiveXObject( " Microsoft.XMLHTTP " ); } } else if (XMLHttpRequest) { // this works for Firefox, Safari, Opera xhr = new XMLHttpRequest(); } else { alert( " 对不起,你的浏览器不支持ajax " ); } return xhr; } function getMessage() { // get our xml http request object var xhr = getXmlHttpRequest(); // prepare the request xhr.open( " GET " , " Comment/AddCommentServer?comment= " + document.getElementById( " Comment " ).value, true ) // setup the callback function xhr.onreadystatechange = function() { // readyState 4 means we're done if (xhr.readyState != 4 ) return ; // populate the page with the result document.getElementById( ' comments ' ).innerHTML = document.getElementById( ' comments ' ).innerHTML + xhr.responseText; }; // fire our request xhr.send( null ); } 在View中引入此脚本,创建一个简单的表单,并添加触发的代码:
< asp:Content ID = " Content2 " ContentPlaceHolderID = " MainContent " runat = " server " > < h4 > Comments </ h4 > < ul id = " comments " > </ ul > <%= Html.TextArea( " Comment " , new {rows = 5 , cols = 50 }) %> < button type = " submit " onclick = " getMessage() " > Add Comment </ button > < span id = " indicator " style = " display:none " >< img src = " http://www.cnblogs.com/content/load.gif " alt = " loading... " /></ span > </ asp:Content > < asp:Content ID = " Content3 " ContentPlaceHolderID = " headContent " runat = " server " > < script src = " http://www.cnblogs.com/Scripts/custom_ajax.js " type = " text/javascript " ></ script > </ asp:Content > 效果如下:
第二种方式:利用Jquery:
在控制器中添加代码IndexJquery方法和AddComment方法的代码,CommentController代码如下所示:
public class CommentController : Controller{ private IList < string > _comments = new List < string > (); public ActionResult Index() { return View(); } public ActionResult IndexJquery() { return View(); } public ActionResult AddComment( string comment) { _comments.Add( " <li> " + comment + " </li> " ); return Content( string .Join( " \n " , _comments.ToArray())); } public void AddCommentServer() { string comment = Request[ " comment " ].ToUpper(); _comments.Add( " <li> " + comment + " </li> " ); Response.ContentType = " text/html " ; Response.Write( string .Join( " \n " , _comments.ToArray())); }} 根据IndexJquery,创建View表单IndexJquery.aspx:
< h4 > Comments </ h4 > < ul id = " comments " > </ ul > <% using (Html.BeginForm( " AddComment " , " Comment " ,FormMethod.Post, new {@class = " hijax " })) { %> <%= Html.TextArea( " Comment " , new {rows = 5 , cols = 50 }) %> < button type = " submit " > Add Comment </ button > < span id = " indicator " style = " display:none " >< img src = " http://www.cnblogs.com/content/load.gif " alt = " loading... " /></ span > <% } %> 在View中引用Jquery:<script src="http://www.cnblogs.com/Scripts/jquery-1.4.1.min.js" type="text/javascript">script>
添加下面脚本:
< script type = " text/javascript " > // execute when the DOM has been loaded $(document).ready(function () { // wire up to the form submit event $( " form.hijax " ).submit(function ( event ) { event .preventDefault(); // prevent the actual form post hijack( this , update_sessions, " html " ); }); }); function hijack(form, callback, format) { $( " #indicator " ).show(); $.ajax({ url: form.action, type: form.method, dataType: format, data: $(form).serialize(), completed: $( " #indicator " ).hide(), success: callback }); } function update_sessions(result) { // clear the form $( " form.hijax " )[ 0 ].reset(); $( " #comments " ).append(result); } </ script > 效果:与方式一效果一样。
第三种方式:Ajax Helper
将最简单的留言板修改成Ajax Helper的方式。
1、首先了解一下Ajax Helper下面四种方法。
a、Ajax.ActionLink():它将渲染成一个超链接的标签,类似于Html.ActionLink()。当它被点击之后,将获取新的内容并将它插入到HTML页面中。
b、Ajax.BeginForm():它将渲染成一个HTML的Form表单,类似于Html.BeginForm()。当它提交之后,将获取新的内容并将它插入到HTML页面中。
c、Ajax.RouteLink():Ajax.RouteLink()类似于Ajax.ActionLink()。不过它可以根据任意的routing参数生成URL,不必包含调用的action。使用最多的场景是自定义的IController,里面没有action。
d、Ajax.BeginRouteForm():同样Ajax.BeginRouteForm()类似于Ajax.BeginForm()。这个Ajax等同于Html.RouteLink()。
这个例子中使用Ajax.BeginForm(),下面具体了解Ajax.BeginForm()的参数。看下面代码:
<% using (Ajax.BeginForm( " AddComment " , new AjaxOptions { HttpMethod = " POST " , UpdateTargetId = " comments " , InsertionMode = InsertionMode.InsertAfter })) { %> actionName: AddComment(action的名字)
controllerName:CommentController(Controller的名字)
ajaxOptions:
HttpMethod:Ajax的请求方式,这里为POST
UpdateTargetId :Ajax请求的结果显示的标签的ID,这里为comments
InsertionMode:将Ajax结果插入页面的方式,这里将ajax的结果放置到comments的后面
2、实现:
在CommentController中添加IndexAjaxHelp方法。
public ActionResult IndexAjaxHelp(){ return View();} 根据IndexAjaxHelp生成View表单IndexAjaxHelp.aspx,定义表单:
< h4 > Comments </ h4 > < ul id = " comments " > </ ul > <% using (Ajax.BeginForm( " AddComment " , new AjaxOptions { HttpMethod = " POST " , UpdateTargetId = " comments " , InsertionMode = InsertionMode.InsertAfter })) { %> <%= Html.TextArea( " Comment " , new {rows = 5 , cols = 50 }) %> < button type = " submit " > Add Comment </ button > <% } %> 要在此View中添加下面两个脚本文件:
<script src="http://www.cnblogs.com/Scripts/MicrosoftAjax.js" type="text/javascript">script>
<script src="http://www.cnblogs.com/Scripts/MicrosoftMvcAjax.js" type="text/javascript">script>
这样就行了,我们发现比用Jquery方便很多,但是使用Jquery将灵活很多。
3、效果:和方式一样。
总结:本文非常的简单,在asp.net mvc中实现了3中ajax的调用方式,实现了一个最简单的留言板程序。推荐使用Jquery和Ajax Helper这两种。Ajax Helper使用非常简单,Jquery比较灵活。
更新:三种方式都实现了一个最简单的留言板程序
参考:
ASP.NET MVC 2 In Action
Pro ASP.NET MVC 2 Framework, Second Edition
代码: