ASP.NET AJAX UpdatePanel 控件实现剖析

最新推荐文章于 2025-11-22 14:31:24 发布

最新推荐文章于 2025-11-22 14:31:24 发布 · 86 阅读

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本文详细解析了ASP.NET AJAX框架中的UpdatePanel控件的工作原理。通过UpdatePanel可以在不刷新整个页面的情况下局部更新内容，提高了用户体验。文章深入探讨了客户端与服务器端的交互流程，包括异步回发机制及页面生命周期的变化。

使用ASP.NET AJAX框架我们可以搭建快速响应、具有丰富的用户体验的AJAX Web应用程序，而该框架的UpdatePanel控件则提供了一种非常简单的方式来实现Web页面的局部更新，我们不需要在每次回发的时候都加载整个页面。

那这个控件是如何实现这种局部刷新的哪，透过其实现机制我们可以更清楚其优缺点，便于我们确定其使用场合。本文将重点阐述ASP.NET AJAX控件UpdatePanel的实现机制。

1． ASP.NET AJAX 简介 ASP.NET AJAX是微软在ASP.NET 2.0之上对AJAX技术的一个封装，为Web应用程序提供完整的AJAX解决方案。ASP.NET AJAX有两种编程模型：部分更新和远程服务。

部分更新使得用户可以用传统的ASP.NET 2.0应用程序的方式来搭建AJAX应用，具体就是使用UpdatePanel控件来实现无闪烁页面更新。而远程服务则是直接通过前端JavaScript来调用的服务器端服务，前段获取数据后，进行页面更新，这就要求服务器端代码必须分解为特定于应用程序的服务，这是与传统的ASP.NET应用程序完全不同的体系结构。

部分更新着重于对现有应用程序进行渐进式增强，帮助用户逐渐转换到纯粹的AJAX应用。本文主要对部分更新编程模型中核心控件UpdatePanel的实现进行剖析，讲述其背后的故事。

ASP.NET AJAX框架分为客户端以及服务器端两个部分，基于客户端的 Microsoft AJAX Library包含了对浏览器兼容性、网络访问以及客户端控件组件等支持，而服务器端则包括了服务器控件，Web 服务等等。

见下图：

Microsoft Ajax Library就是ASP.NET AJAX的客户端脚本库，其中MicrosoftAjax.js包含了ASP.NET AJAX的核心内容，包括跨浏览器的支持、基于面向对象对JavaScript的扩展以及网络访问等等。MicrosoftAjaxWebForm.js文件则是完全服务于ASP.NET AJAX页面局部更新这样一个功能的，在该文件中定义了一个客户端对象PageRequestManager，该对象将会负责客户端异步回送的全过程。

2． ScriptManager 和 UpdatePanel ScriptManager和UpdatePanel是ASP.NET AJAX服务器端中最重要的两个控件，ScriptManager控件用来管理ASP.NET页面中的客户端脚本，生成及注册所需要的客户端脚本，通过UpdatePanel控件可以更新页面的指定部分而无需加载整个页面。

看个例子：

 
<form id="form1" runat="server">  

<asp:ScriptManager ID="ScriptManager1" runat="server">  

</asp:ScriptManager>  

<div>  

<asp:UpdatePanel ID="UpdatePanel1" runat="server">  

<ContentTemplate>  

<%= DateTime.Now %>  

<br />  

<asp:Button ID="Button1" runat="server" Text="Button" />  

</ContentTemplate>  

</asp:UpdatePanel>  

</div>  

</form>

构建如上代码所示的页面，在Runtime点击UpdatePanel中的Button控件，则不会引起整个页面刷新，只是用来显示当前时间的Label得到更新。

这是如何实现的哪？

3． ASP.NET AJAX部分呈现剖析

3.1 先从客户端讲起

看一下上面的示例代码在客户端的HTML代码，这里只列出核心部分，其他全部隐去。

 
<script type="text/javascript">  

//<![CDATA[  

   03Sys.WebForms.PageRequestManager._initialize('ScriptManager1', document.getElementById('form1')); 

   04Sys.WebForms.PageRequestManager.getInstance()._updateControls(['tUpdatePanel1'], [], [], 90); 

   05//]]>

</script>  



<div id="UpdatePanel1">  

7/25/2008 4:54:36 PM  

<br />  

<input type="submit" name="Button1" value="Button" id="Button1" />  

</div>

看一下上面的两句JavaScript代码，第一句代码中的_initialize 方法是客户端PageRequestManager对象上的静态方法，它会创建一个 PageRequestManager 类的全局实例，并将其初始化。在这个初始化函数中，ageRequestManager对象注册了当前表单对象的submit事件，以及window对象的load和unload事件。

而第二句代码则是通过PageRequestManager的getInstance方法来检索其唯一实例，得到该实例后调用_updateControls方法来注册UpdatePanel以及其Trigger控件。

我们可以从MicrosoftAjaxWebForm.js文件中得到_updateControls方法的声明：

 
   1function Sys$WebForms$PageRequestManager$_updateControls(updatePanelIDs, asyncPostBackControlIDs, postBackControlIDs, asyncPostBackTimeout) {}

由其中第一个参数代表了当前页面上所有的UpdatePanel控件的ID集合，如果该UpdatePanel的ChildrenAsTrigger为True的话，应在ID前添加字符't'，否则添加字符'f'；而第二个参数是所有引发异步回送的控件ID；第三个参数是所有引发同步回送的控件ID；第四个参数设定了异步回送的Timeout时间，单位为秒。于PageRequestManager对象注册了当前表单的submit时间，所以每当页面有提交动作的时候，PageRequestManager对象就会介入，看一下PageRequestManager对象页面提交处理函数_onFormSubmit(evt)。

如果需要执行一次异步回送的话，会中止原有的普通浏览器会回发，代之使用XMLHttpRequest进行AJAX回发。在封装这个请求的时候，当前页面的所有字段以及视图状态都会被打包在请求中，另外还设置了这次Request的HTTP头：request.get_headers()['X-MicrosoftAjax'] = 'Delta=true'；

在服务器端将会根据这个HTTP头标记来判定是否为一次AJAX异步回发。

_onFormSubmit(evt)函数代码：

 
   001function Sys$WebForms$PageRequestManager$_onFormSubmit(evt) { 

var continueSubmit = true;  

var isCrossPost = this._isCrossPost;  

this._isCrossPost = false;  

if (this._onsubmit) {  

continueSubmit = this._onsubmit();  

}  

if (continueSubmit) {  

for (var i = 0; i < this._onSubmitStatements.length; i++) {  

if (!this._onSubmitStatements[i]()) {  

continueSubmit = false;  

break;  

}  

}  

}  

if (!continueSubmit) {  

if (evt) {  

evt.preventDefault();  

}  

return;  

}  

var form = this._form;  

if (isCrossPost) {  

return;  

}  

if (this._activeDefaultButton && !this._activeDefaultButtonClicked) {  

this._onFormElementActive(this._activeDefaultButton, 0, 0);  

}  

if (!this._postBackSettings.async) {  

return;  

}  

var formBody = new Sys.StringBuilder();  

formBody.append(encodeURIComponent(this._scriptManagerID) + '=' + encodeURIComponent(this._postBackSettings.panelID) + '&');  

var count = form.elements.length;  

for (var i = 0; i < count; i++) {  

var element = form.elements[i];  

var name = element.name;  

if (typeof(name) === "undefined" || (name === null) || (name.length === 0)) {  

continue;  

}  

var tagName = element.tagName;  

if (tagName === 'INPUT') {  

var type = element.type;  

if ((type === 'text') ||  

(type === 'password') ||  

(type === 'hidden') ||  

(((type === 'checkbox') || (type === 'radio')) && element.checked)) {  

formBody.append(encodeURIComponent(name));  

formBody.append('=');  

formBody.append(encodeURIComponent(element.value));  

formBody.append('&');  

}  

}  

else if (tagName === 'SELECT') {  

var optionCount = element.options.length;  

for (var j = 0; j < optionCount; j++) {  

var option = element.options[j];  

if (option.selected) {  

formBody.append(encodeURIComponent(name));  

formBody.append('=');  

formBody.append(encodeURIComponent(option.value));  

formBody.append('&');  

}  

}  

}  

else if (tagName === 'TEXTAREA') {  

formBody.append(encodeURIComponent(name));  

formBody.append('=');  

formBody.append(encodeURIComponent(element.value));  

formBody.append('&');  

}  

}  

if (this._additionalInput) {  

formBody.append(this._additionalInput);  

this._additionalInput = null;  

}  



var request = new Sys.Net.WebRequest();  

var action = form.action;  

if (Sys.Browser.agent === Sys.Browser.InternetExplorer) {  

var queryIndex = action.indexOf('?');  

if (queryIndex !== -1) {  

var path = action.substr(0, queryIndex);  

if (path.indexOf("%") === -1) {  

action = encodeURI(path) + action.substr(queryIndex);  

}  

}  

else if (action.indexOf("%") === -1) {  

action = encodeURI(action);  

}  

}  

request.set_url(action);  

request.get_headers()['X-MicrosoftAjax'] = 'Delta=true';  

request.get_headers()['Cache-Control'] = 'no-cache';  

request.set_timeout(this._asyncPostBackTimeout);  

request.add_completed(Function.createDelegate(this, this._onFormSubmitCompleted));  

request.set_body(formBody.toString());  

var handler = this._get_eventHandlerList().getHandler("initializeRequest");  

if (handler) {  

var eventArgs = new Sys.WebForms.InitializeRequestEventArgs(request, this._postBackSettings.sourceElement);  

handler(this, eventArgs);  

continueSubmit = !eventArgs.get_cancel();  

}  

if (!continueSubmit) {  

if (evt) {  

evt.preventDefault();  

}  

return;  

}  

this._scrollPosition = this._getScrollPosition();  

this.abortPostBack();  

handler = this._get_eventHandlerList().getHandler("beginRequest");  

if (handler) {  

var eventArgs = new Sys.WebForms.BeginRequestEventArgs(request, this._postBackSettings.sourceElement);  

handler(this, eventArgs);  

}  



if (this._originalDoCallback) {  

this._cancelPendingCallbacks();  

}  

this._request = request;  

request.invoke();  

if (evt) {  

evt.preventDefault();  

}  

}

我们可以发现AJAX回发所提交的数据量其实跟普通回发过程中提交的数据量是一样的，并且还附加了一些额外信息。

3.2 服务器端的处理

AJAX回发请求到达服务器之后，当前页面的生命周期跟普通回发引起的请求是一样的，页面的Init、Load和Render等等事件都会被触发，差别只是在于AJAX回发使用了不同的呈现画法。

AJAX回发引起的请求生命周期：

从上图我们可以看到，页面的生命周期与普通回发是一样的，同样页面上的控件也会经历相应的生命周期。

先了解一下ScriptManager控件在服务器端的处理：

- OnInit：在Init事件中，ScriptManager控件会注册页面的InitComplete, PreRenderComplete以及PreRender事件，另外还会根据本次请求的HTTP头来设定一个标记以确定本次回发是否为Ajax异步更新所引起的回发。

见下面的代码：

 
protected internal override void OnInit(EventArgs e)  

   02{ 

base.OnInit(e);  

if (this.EnableHistory)  

{  

this.RegisterAsyncPostBackControl(this);  

}  

if (!base.DesignMode)  

{  

IPage iPage = this.IPage;  

if (GetCurrent(this.Page) != null)  

{  

throw new InvalidOperationException(AtlasWeb.ScriptManager_OnlyOneScriptManager);  

}  

iPage.Items[typeof(IScriptManager)] = this;  

iPage.Items[typeof(ScriptManager)] = this;  

iPage.InitComplete += new EventHandler(this.OnPageInitComplete);  

iPage.PreRenderComplete += new EventHandler(this.OnPagePreRenderComplete);  

if (iPage.IsPostBack)  

{  

this._isInAsyncPostBack = PageRequestManager.IsAsyncPostBackRequest(iPage.Request.Headers);  

if (this.EnableHistory)  

{  

this._isNavigating = iPage.Request["__EVENTTARGET"] == this.UniqueID;  

}  

}  

this.PageRequestManager.OnInit();  

iPage.PreRender += new EventHandler(this.ScriptControlManager.OnPagePreRender);  

}  

   30}

- OnPagePreRenderComplete，在PagePreRenderComplete事件中，ScriptManager控件会注册脚本文件以及Services代理脚本，MicrosoftAjax.js和MicrosoftAjaxWebForm.js就是在这个阶段被注册到客户端的。

见下面的代码：

 
private void OnPagePreRenderComplete(object sender, EventArgs e)  

   02{ 

if (!this.IsInAsyncPostBack)  

{  

if (this.SupportsPartialRendering)  

{  

this.IPage.ClientScript.GetPostBackEventReference(new PostBackOptions(this, null, null, false, false, false, false, true, null));  

}  

this.RegisterGlobalizationScriptBlock();  

this.RegisterScripts();  

this.RegisterServices();  

if (this.EnableHistory)  

{  

JavaScriptSerializer serializer = JavaScriptSerializer.CreateInstance();  

string[] strArray = new string[] { "/r/nSys.Application.setServerId(", serializer.Serialize(this.ClientID), ", ", serializer.Serialize(this.UniqueID), ");/r/n", ((this._initialState != null) && (this._initialState.Count != 0)) ? (" Sys.Application.setServerState('" + this.GetStateString() + "');/r/n") : "/r/n" };  

string script = string.Concat(strArray);  

RegisterStartupScript(this, typeof(ScriptManager), "HistoryStartup", script, true);  

}  

}  

else 

{  

this.RegisterScripts();  

if (this.EnableHistory)  

{  

if ((this._initialState != null) && (this._initialState.Count == 0))  

{  

this._initialState = null;  

}  

if (this._newPointCreated)  

{  

this.RegisterDataItem(this, "'" + this.GetStateString() + "'", true);  

}  

}  

}  

   35}

- OnPreRender，在PreRender事件中如果判定本次回发为AJAX回发，则会调用PageRequestManager对象的OnPreRender方法。而PageRequestManager对象则会调用Page对象的SetRenderMethodDelegate方法来代理Page的画法，PageRequestManager对象会真正负责本次AJAX回发最终的HTML代码。

见下面的代码：

 
public class ScriptManager : Control,  

   02{ 

protected internal override void OnPreRender(EventArgs e)  

{  

base.OnPreRender(e);  

if (this.IsInAsyncPostBack)  

{  

this.PageRequestManager.OnPreRender();  

}  

}  

   11} 



internal sealed class PageRequestManager  

   14{ 

internal void OnPreRender()  

{  

this._owner.IPage.SetRenderMethodDelegate(new RenderMethod(this.RenderPageCallback));  

}  

   19}

PageRequestManager的RenderPageCallback方法最终处理了AJAX回发所需要的HTML代码，在这个方法中会遍历页面上所有涉及到的UpdatePanel控件，得到其更新后的HTML代码后，与隐藏字段还有一些额外信息一起打包，然后传递给客户端。

见下面的代码：

 
private void RenderPageCallback(HtmlTextWriter writer, Control pageControl)  

   02{ 

this.ProcessUpdatePanels();  

IHttpResponse response = this._owner.IPage.Response;  

response.ContentType = "text/plain";  

response.Cache.SetNoServerCaching();  

IHtmlForm form = this._owner.IPage.Form;  

form.SetRenderMethodDelegate(new RenderMethod(this.RenderFormCallback));  

this._updatePanelWriter = writer;  

ParserStringWriter writer2 = new ParserStringWriter();  

ParserHtmlTextWriter writer3 = new ParserHtmlTextWriter(writer2);  

writer2.ParseWrites = true;  

form.RenderControl(writer3);  

writer2.ParseWrites = false;  

foreach (KeyValuePair<string, string> pair in writer2.HiddenFields)  

{  

if (ControlUtil.IsBuiltInHiddenField(pair.Key))  

{  

EncodeString(writer, "hiddenField", pair.Key, pair.Value);  

}  

}  

EncodeString(writer, "asyncPostBackControlIDs", string.Empty, this.GetAsyncPostBackControlIDs(false));  

EncodeString(writer, "postBackControlIDs", string.Empty, this.GetPostBackControlIDs(false));  

EncodeString(writer, "updatePanelIDs", string.Empty, this.GetAllUpdatePanelIDs());  

EncodeString(writer, "childUpdatePanelIDs", string.Empty, this.GetChildUpdatePanelIDs());  

EncodeString(writer, "panelsToRefreshIDs", string.Empty, this.GetRefreshingUpdatePanelIDs());  

EncodeString(writer, "asyncPostBackTimeout", string.Empty, this._owner.AsyncPostBackTimeout.ToString(CultureInfo.InvariantCulture));  

if (writer3.FormAction != null)  

{  

EncodeString(writer, "formAction", string.Empty, writer3.FormAction);  

}  

if (this._owner.IPage.Header != null)  

{  

string title = this._owner.IPage.Title;  

if (!string.IsNullOrEmpty(title))  

{  

EncodeString(writer, "pageTitle", string.Empty, title);  

}  

}  

this.RenderDataItems(writer);  

this.ProcessScriptRegistration(writer);  

this.ProcessFocus(writer);  

   43}

3.3 客户端更新

当服务器端相应完毕后，客户端会得到响应信息，然后调用客户端对象PageRequestManager的_onFormSubmitCompleted方法来进行页面局部更新，最终会调用_updatePanel方法来更新UpdatePanel控件。

参见_onFormSubmitCompleted方法的代码：

 
   001function Sys$WebForms$PageRequestManager$_onFormSubmitCompleted(sender, eventArgs) { 

this._processingRequest = true;  

var delimitByLengthDelimiter = '|';  

if (sender.get_timedOut()) {  

this._endPostBack(this._createPageRequestManagerTimeoutError(), sender);  

return;  

}  

if (sender.get_aborted()) {  

this._endPostBack(null, sender);  

return;  

}  

if (!this._request || sender.get_webRequest() !== this._request) {  

return;  

}  

var errorMessage;  

var delta = [];  

if (sender.get_statusCode() !== 200) {  

this._endPostBack(this._createPageRequestManagerServerError(sender.get_statusCode()), sender);  

return;  

}  

var reply = sender.get_responseData();  

var delimiterIndex, len, type, id, content;  

var replyIndex = 0;  

var parserErrorDetails = null;  

while (replyIndex < reply.length) {  

delimiterIndex = reply.indexOf(delimitByLengthDelimiter, replyIndex);  

if (delimiterIndex === -1) {  

parserErrorDetails = this._findText(reply, replyIndex);  

break;  

}  

len = parseInt(reply.substring(replyIndex, delimiterIndex), 10);  

if ((len % 1) !== 0) {  

parserErrorDetails = this._findText(reply, replyIndex);  

break;  

}  

replyIndex = delimiterIndex + 1;  

delimiterIndex = reply.indexOf(delimitByLengthDelimiter, replyIndex);  

if (delimiterIndex === -1) {  

parserErrorDetails = this._findText(reply, replyIndex);  

break;  

}  

type = reply.substring(replyIndex, delimiterIndex);  

replyIndex = delimiterIndex + 1;  

delimiterIndex = reply.indexOf(delimitByLengthDelimiter, replyIndex);  

if (delimiterIndex === -1) {  

parserErrorDetails = this._findText(reply, replyIndex);  

break;  

}  

id = reply.substring(replyIndex, delimiterIndex);  

replyIndex = delimiterIndex + 1;  

if ((replyIndex + len) >= reply.length) {  

parserErrorDetails = this._findText(reply, reply.length);  

break;  

}  

content = reply.substr(replyIndex, len);  

replyIndex += len;  

if (reply.charAt(replyIndex) !== delimitByLengthDelimiter) {  

parserErrorDetails = this._findText(reply, replyIndex);  

break;  

}  

replyIndex++;  

Array.add(delta, {type: type, id: id, content: content});  

}  

if (parserErrorDetails) {  

this._endPostBack(this._createPageRequestManagerParserError(String.format(Sys.WebForms.Res.PRM_ParserErrorDetails, parserErrorDetails)), sender);  

return;  

}  

var updatePanelNodes = [];  

var hiddenFieldNodes = [];  

var arrayDeclarationNodes = [];  

var scriptBlockNodes = [];  

var scriptStartupNodes = [];  

var expandoNodes = [];  

var onSubmitNodes = [];  

var dataItemNodes = [];  

var dataItemJsonNodes = [];  

var scriptDisposeNodes = [];  

var asyncPostBackControlIDsNode, postBackControlIDsNode,  

updatePanelIDsNode, asyncPostBackTimeoutNode,  

childUpdatePanelIDsNode, panelsToRefreshNode, formActionNode;  

for (var i = 0; i < delta.length; i++) {  

var deltaNode = delta[i];  

switch (deltaNode.type) {  

case "updatePanel":  

Array.add(updatePanelNodes, deltaNode);  

break;  

case "hiddenField":  

Array.add(hiddenFieldNodes, deltaNode);  

break;  

case "arrayDeclaration":  

Array.add(arrayDeclarationNodes, deltaNode);  

break;  

case "scriptBlock":  

Array.add(scriptBlockNodes, deltaNode);  

break;  

case "scriptStartupBlock":  

Array.add(scriptStartupNodes, deltaNode);  

break;  

case "expando":  

Array.add(expandoNodes, deltaNode);  

break;  

case "onSubmit":  

Array.add(onSubmitNodes, deltaNode);  

break;  

case "asyncPostBackControlIDs":  

asyncPostBackControlIDsNode = deltaNode;  

break;  

case "postBackControlIDs":  

postBackControlIDsNode = deltaNode;  

break;  

case "updatePanelIDs":  

updatePanelIDsNode = deltaNode;  

break;  

case "asyncPostBackTimeout":  

asyncPostBackTimeoutNode = deltaNode;  

break;  

case "childUpdatePanelIDs":  

childUpdatePanelIDsNode = deltaNode;  

break;  

case "panelsToRefreshIDs":  

panelsToRefreshNode = deltaNode;  

break;  

case "formAction":  

formActionNode = deltaNode;  

break;  

case "dataItem":  

Array.add(dataItemNodes, deltaNode);  

break;  

case "dataItemJson":  

Array.add(dataItemJsonNodes, deltaNode);  

break;  

case "scriptDispose":  

Array.add(scriptDisposeNodes, deltaNode);  

break;  

case "pageRedirect":  

if (Sys.Browser.agent === Sys.Browser.InternetExplorer) {  

var anchor = document.createElement("a");  

anchor.style.display = 'none';  

anchor.attachEvent("onclick", cancelBubble);  

anchor.href = deltaNode.content;  

document.body.appendChild(anchor);  

anchor.click();  

anchor.detachEvent("onclick", cancelBubble);  

document.body.removeChild(anchor);  



function cancelBubble(e) {  

e.cancelBubble = true;  

}  

}  

else {  

window.location.href = deltaNode.content;  

}  

return;  

case "error":  

this._endPostBack(this._createPageRequestManagerServerError(Number.parseInvariant(deltaNode.id), deltaNode.content), sender);  

return;  

case "pageTitle":  

document.title = deltaNode.content;  

break;  

case "focus":  

this._controlIDToFocus = deltaNode.content;  

break;  

default:  

this._endPostBack(this._createPageRequestManagerParserError(String.format(Sys.WebForms.Res.PRM_UnknownToken, deltaNode.type)), sender);  

return;  

}  

}  

var i;  

if (asyncPostBackControlIDsNode && postBackControlIDsNode &&  

updatePanelIDsNode && panelsToRefreshNode &&  

asyncPostBackTimeoutNode && childUpdatePanelIDsNode) {  

this._oldUpdatePanelIDs = this._updatePanelIDs;  

var childUpdatePanelIDsString = childUpdatePanelIDsNode.content;  

this._childUpdatePanelIDs = childUpdatePanelIDsString.length ? childUpdatePanelIDsString.split(',') : [];  

var asyncPostBackControlIDsArray = this._splitNodeIntoArray(asyncPostBackControlIDsNode);  

var postBackControlIDsArray = this._splitNodeIntoArray(postBackControlIDsNode);  

var updatePanelIDsArray = this._splitNodeIntoArray(updatePanelIDsNode);  

this._panelsToRefreshIDs = this._splitNodeIntoArray(panelsToRefreshNode);  

for (i = 0; i < this._panelsToRefreshIDs.length; i++) {  

var panelClientID = this._uniqueIDToClientID(this._panelsToRefreshIDs[i]);  

if (!document.getElementById(panelClientID)) {  

this._endPostBack(Error.invalidOperation(String.format(Sys.WebForms.Res.PRM_MissingPanel, panelClientID)), sender);  

return;  

}  

}  

var asyncPostBackTimeout = asyncPostBackTimeoutNode.content;  

this._updateControls(updatePanelIDsArray, asyncPostBackControlIDsArray, postBackControlIDsArray, asyncPostBackTimeout);  

}  

this._dataItems = {};  

for (i = 0; i < dataItemNodes.length; i++) {  

var dataItemNode = dataItemNodes[i];  

this._dataItems[dataItemNode.id] = dataItemNode.content;  

}  

for (i = 0; i < dataItemJsonNodes.length; i++) {  

var dataItemJsonNode = dataItemJsonNodes[i];  

this._dataItems[dataItemJsonNode.id] = Sys.Serialization.JavaScriptSerializer.deserialize(dataItemJsonNode.content);  

}  

var handler = this._get_eventHandlerList().getHandler("pageLoading");  

if (handler) {  

handler(this, this._getPageLoadingEventArgs());  

}  

if (formActionNode) {  

this._form.action = formActionNode.content;  

}  





Sys._ScriptLoader.readLoadedScripts();  

Sys.Application.beginCreateComponents();  

var scriptLoader = Sys._ScriptLoader.getInstance();  

this._queueScripts(scriptLoader, scriptBlockNodes, true, false);  



this._updateContext = {  

response: sender,  

updatePanelNodes: updatePanelNodes,  

scriptBlockNodes: scriptBlockNodes,  

scriptDisposeNodes: scriptDisposeNodes,  

hiddenFieldNodes: hiddenFieldNodes,  

arrayDeclarationNodes: arrayDeclarationNodes,  

expandoNodes: expandoNodes,  

scriptStartupNodes: scriptStartupNodes,  

onSubmitNodes: onSubmitNodes  

};  

scriptLoader.loadScripts(0,  

Function.createDelegate(this, this._scriptIncludesLoadComplete),  

Function.createDelegate(this, this._scriptIncludesLoadFailed),  

null);  

   227}