【深入ASP.NET原理系列】--ASP.NET页面生命周期

2019-11-14 14:32:24

字体：大中小

来源：转载

供稿：网友

前言

asp.net页面运行时候，页面将经历一个生命周期，在生命周期中将执行一系列的处理步骤。包括初始化、实例化控件、还原和维护状态、运行时间处理程序代码以及进行呈现。熟悉页面生命周期非常重要，这样我们才能在生命周期的合适阶段编写代码。如果我们能在写代码的时候想着我们现在是在做生命周期的哪一步那将是非常好的。

你可能会说我不清楚还不是一样写代码，反正每次都在Page_load里面写代码然后页面就出来了我管那么多干什么。所谓知其然如果能知其所以然岂不是更吊？我个人认为做ASP.NET B/S开发只要咱们熟悉ASP.NET页面生命周期，熟悉“请求-处理-响应“模式，对于一时半儿没有触及到的细节，等真正遇到那个点再去理解它也是毫不费力的。

几个代表性的问题

在开始的时候我们先思考几个问题，看看我们在描述完页面生命周期的时候，能不能回答上这几个问题

1.为什么在服务器端能通过this.textbox1.Text获取到用户提交过来的数据？

2.在Page_Load中Response.Write("hello")查看生成的html代码原文件，hello在哪里？为什么？

3.有一个服务器端的按钮，设置了点击事件，该点击事件什么时候执行？是先执行Page_Load事件还是先执行点击事件？

4.为什么在服务器端通过this.textbox1.Text设置值后，客户端就能显示出来？

看过我上一篇博客【深入ASP.NET原理系列】--ASP.NET请求管道、应用程序生命周期、整体运行机制童鞋可能知道，ASP.NET应用程序周期中PReRequestHandlerExecute事件与PostRequestHandlerExecute事件之间就是我们的页面生命周期了，对于aspx页面就是一系列的打造页面控件树，触发各种页面时间，对于一般处理程序ashx就是直接执行咱们开发者写的ProcessRequest方法了，对于MVC应用程序就是创建控制器工厂，创建控制器对象，调用Action那一套了。

下面主要讲述的就是ASP.NET WebForm中的页面的生命周期了。

我们用反编译工具查看Page类的ProcessRequest方法可以看见先调用了FrameworkInitialize; FrameworkInitialize里面就是打造了页面控件树，然后调用了ProcessRequestMain，就开始了执行整个页面生命周期了（其实就是调用了一系列的事件方法）（可能部分图看不见右边，可在新标签页中打开图片）

1.打造页面控件树

FrameworkInitialize内部调用了_buildControlTree（）方法

　　

上图中左边是前台页面的代码，右边是对应 生成的打造控件树的代码。中间截取的是生成表单那一部分的代码。

下面看一张原理图

浏览器的DOM树是根据Html标签生成一个C语言的DOM树，而ASP.NET服务器端是用C#打造的一个控件树，也是按照DOM结构打造的。本质是一样。服务器端所有东西都加到页面对象的控件集合中去了。标签在服务器端有对应的控件对象的时候就用控件对象，没有的时候就使用LiteralControl进行封装。不管是服务器控件还是字符串标签（没有runat="server"的标签）都以控件对象的方式存在前台页面类的控件集合里面。好处就是生成前台页面的html代码的时候，只需要遍历控件集合里面的每一个控件对象的RenderControl方法，每一个控件都会调用自己的Render方法生成对应的Html字符串。那么所有控件的生成的html字符串就还原成一个页面的html代码了。

2.触发PerformPreInit事件　

在所有初始化之前初始化了这个事件，这个事件主要是初始化了主题，初始化了母版页

 1 private void PerformPreInit() 2  3 { 4  5     this.OnPreInit(EventArgs.Empty); 6  7     this.InitializeThemes(); 8  9     this.ApplyMasterPage();10 11     this._preInitWorkComplete = true;12 13 }

View Code

3.触发InitRecursive事件

4.触发LoadAllState()事件

加载页面状态解析ViewState，将页面表单中的ViewState进行反Base64编码，反序列化，存在页面的ViewState属性中

5.触发ProcessPostData(this._requestValueCollection, true)事件

 1 private void ProcessPostData(NameValueCollection postData, bool fBeforeLoad) 2 { 3     if (this._changedPostDataConsumers == null) 4     { 5         this._changedPostDataConsumers = new ArrayList(); 6     } 7     if (postData != null) 8     { 9         foreach (string str in postData)10         {11             if ((str != null) && !IsSystemPostField(str))12             {13                 Control control = this.FindControl(str);14                 if (control == null)15                 {16                     if (fBeforeLoad)17                     {18                         if (this._leftoverPostData == null)19                         {20                             this._leftoverPostData = new NameValueCollection();21                         }22                         this._leftoverPostData.Add(str, null);23                     }24                 }25                 else26                 {27                     ipostBackDataHandler postBackDataHandler = control.PostBackDataHandler;28                     if (postBackDataHandler == null)29                     {30                         if (control.PostBackEventHandler != null)31                         {32                             this.RegisterRequiresRaiseEvent(control.PostBackEventHandler);33                         }34                     }35                     else36                     {37                         if (postBackDataHandler != null)38                         {39                             NameValueCollection postCollection = control.CalculateEffectiveValidateRequest() ? this._requestValueCollection : this._unvalidatedRequestValueCollection;40                             if (postBackDataHandler.LoadPostData(str, postCollection))41                             {42                                 this._changedPostDataConsumers.Add(control);43                             }44                         }45                         if (this._controlsRequiringPostBack != null)46                         {47                             this._controlsRequiringPostBack.Remove(str);48                         }49                     }50                 }51             }52         }53     }54     ArrayList list = null;55     if (this._controlsRequiringPostBack != null)56     {57         foreach (string str2 in this._controlsRequiringPostBack)58         {59             Control control2 = this.FindControl(str2);60             if (control2 != null)61             {62                 IPostBackDataHandler adapterInternal = control2.AdapterInternal as IPostBackDataHandler;63                 if (adapterInternal == null)64                 {65                     adapterInternal = control2 as IPostBackDataHandler;66                 }67                 if (adapterInternal == null)68                 {69                     object[] args = new object[] { str2 };70                     throw new HttpException(SR.GetString("Postback_ctrl_not_found", args));71                 }72                 NameValueCollection values2 = control2.CalculateEffectiveValidateRequest() ? this._requestValueCollection : this._unvalidatedRequestValueCollection;73                 if (adapterInternal.LoadPostData(str2, values2))74                 {75                     this._changedPostDataConsumers.Add(control2);76                 }77             }78             else if (fBeforeLoad)79             {80                 if (list == null)81                 {82                     list = new ArrayList();83                 }84                 list.Add(str2);85             }86         }87         this._controlsRequiringPostBack = list;88     }89 }90 91  92 93 94

View Code

主要做了两件事

1）将表单里提交过来的控件数据设置给页面对象的控件树中对应控件的属性（给前面打造的控件树里面控件给值），这样在服务器端就可以拿到客户端输入的值了。

2）将表单里面提交过来的值与ViewState中控件原来的值进行比对，不同则表示要触发该控件的Change 事件，则同时将该控件放到一个集合（看源码其实就是changedPostDataConsumers）中。在后续执行过程中遍历改集合依次触发对应控件的Change事件。

6.触发LoadRecursive()事件

大名鼎鼎的Page_Load就是在这里执行的。不过是先执行页面本身的Load事件再执行页面控件的Load事件哦,这时候前面给控件赋的值,表单提交过来的数据,ViewState等等都可以使用了，IsPostBack的原理就是判断是否有name为__VIEWSTATE的数据提交过来

7.再次触发ProcessPostData(this._leftoverPostData, false)事件

这个事件我在网上看了很多人说是将第一次遗漏下来的，第一次执行ProcessPostData没有涉及到的控件进行处理，但是并没有说明哪些遗漏下来了。为什么第一次没处理了？ 最后Google查到是处理我们开发者在页面的Page_Load方法中添加的控件。在Page_Load中我们可以自己创建控件对象加到页面对应的“C#DOM树中“，如：在Page_Load中写
TextBox txt = new TextBox();txt.ID ="myTxtBox";this.form1.Controls.Add(txt);
这就是把开发者自己创建的控件加在页面的form1的表单中。当然你也可以加上Change事件了创建控件的时候。执行的还是上面那两件事了。则回发的时候可以给开发者在Page_Lod中手动创建的控件还原值。

8.触发RaiseChangedEvents事件

循环遍历changedPostDataConsumers集合中的所有控件，依次执行控件的非点击回传事件，比如文本框的改变事件等

9.触发RaisePostBackEvent(this._requestValueCollection)事件

执行按钮点击回传事件或者验证事件，如果有多个按钮，根据回发过来的按钮的 name来判断触发哪个按钮的事件，或者触发该控件的验证事件

10.触发PerformPreRenderComplete事件

循环遍历控件树中所有的控件，根据每个控件生成对应的Html代码，把服务器控件渲染成普通的html控件。

11.触发事件SaveAllState事件

将服务器端ViewState集合中的内容（开发者自己加的数据或控件状态信息等）序列化然后Base64编码然后设置到客户端隐藏域__ViewState中

12.RenderControl(this.CreateHtmlTextWriter(this.Response.Output))

把要发送到客户端浏览器的内容设置到Response.Output，应用程序将它发送 到客户端浏览器。

看到这里不知道大家是否已经可以清晰地回答开篇提到的几个问题了，其实就是这些事件执行的先后顺序，页面生命周期了。”前人植树，后人乘凉了"

最后附上生命周期ProcessRequest源码　　

  1 private void ProcessRequestMain(bool includeStagesBeforeAsyncPoint, bool includeStagesAfterAsyncPoint)  2 {  3     try  4     {  5         HttpContext context = this.Context;  6         string str = null;  7         if (includeStagesBeforeAsyncPoint)  8         {  9             if (this.IsInAspCompatMode) 10             { 11                 AspCompatapplicationStep.OnPageStartsessionObjects(); 12             } 13             if (this.PageAdapter != null) 14             { 15                 this._requestValueCollection = this.PageAdapter.DeterminePostBackMode(); 16                 if (this._requestValueCollection != null) 17                 { 18                     this._unvalidatedRequestValueCollection = this.PageAdapter.DeterminePostBackModeUnvalidated(); 19                 } 20             } 21             else 22             { 23                 this._requestValueCollection = this.DeterminePostBackMode(); 24                 if (this._requestValueCollection != null) 25                 { 26                     this._unvalidatedRequestValueCollection = this.DeterminePostBackModeUnvalidated(); 27                 } 28             } 29             string callbackControlID = string.Empty; 30             if (this.DetermineIsExportingWebPart()) 31             { 32                 if (!RuntimeConfig.GetAppConfig().WebParts.EnableExport) 33                 { 34                     throw new InvalidOperationException(SR.GetString("WebPartExportHandler_DisabledExportHandler")); 35                 } 36                 str = this.Request.QueryString["webPart"]; 37                 if (string.IsNullOrEmpty(str)) 38                 { 39                     throw new InvalidOperationException(SR.GetString("WebPartExportHandler_InvalidArgument")); 40                 } 41                 if (string.Equals(this.Request.QueryString["scope"], "shared", StringComparison.OrdinalIgnoreCase)) 42                 { 43                     this._pageFlags.Set(4); 44                 } 45                 string str3 = this.Request.QueryString["query"]; 46                 if (str3 == null) 47                 { 48                     str3 = string.Empty; 49                 } 50                 this.Request.QueryStringText = str3; 51                 context.Trace.IsEnabled = false; 52             } 53             if (this._requestValueCollection != null) 54             { 55                 if (this._requestValueCollection["__VIEWSTATEENCRYPTED"] != null) 56                 { 57                     this.ContainsEncryptedViewState = true; 58                 } 59                 callbackControlID = this._requestValueCollection["__CALLBACKID"]; 60                 if ((callbackControlID != null) && (this._request.HttpVerb == HttpVerb.POST)) 61                 { 62                     this._isCallback = true; 63                 } 64                 else if (!this.IsCrossPagePostBack) 65                 { 66                     VirtualPath path = null; 67                     if (this._requestValueCollection["__PREVIOUSPAGE"] != null) 68                     { 69                         try 70                         { 71                             path = VirtualPath.CreateNonRelativeAllowNull(DecryptString(this._requestValueCollection["__PREVIOUSPAGE"], Purpose.WebForms_Page_PreviousPageID)); 72                         } 73                         catch 74                         { 75                             this._pageFlags[8] = true; 76                         } 77                         if ((path != null) && (path != this.Request.CurrentExecutionFilePathObject)) 78                         { 79                             this._pageFlags[8] = true; 80                             this._previousPagePath = path; 81                         } 82                     } 83                 } 84             } 85             if (this.MaintainScrollPositionOnPostBack) 86             { 87                 this.LoadScrollPosition(); 88             } 89             if (context.TraceIsEnabled) 90             { 91                 this.Trace.Write("aspx.page", "Begin PreInit"); 92             } 93             if (EtwTrace.IsTraceEnabled(5, 4)) 94             { 95                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_INIT_ENTER, this._context.WorkerRequest); 96             } 97             this.PerformPreInit(); 98             if (EtwTrace.IsTraceEnabled(5, 4)) 99             {100                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_INIT_LEAVE, this._context.WorkerRequest);101             }102             if (context.TraceIsEnabled)103             {104                 this.Trace.Write("aspx.page", "End PreInit");105             }106             if (context.TraceIsEnabled)107             {108                 this.Trace.Write("aspx.page", "Begin Init");109             }110             if (EtwTrace.IsTraceEnabled(5, 4))111             {112                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_INIT_ENTER, this._context.WorkerRequest);113             }114             this.InitRecursive(null);115             if (EtwTrace.IsTraceEnabled(5, 4))116             {117                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_INIT_LEAVE, this._context.WorkerRequest);118             }119             if (context.TraceIsEnabled)120             {121                 this.Trace.Write("aspx.page", "End Init");122             }123             if (context.TraceIsEnabled)124             {125                 this.Trace.Write("aspx.page", "Begin InitComplete");126             }127             this.OnInitComplete(EventArgs.Empty);128             if (context.TraceIsEnabled)129             {130                 this.Trace.Write("aspx.page", "End InitComplete");131             }132             if (this.IsPostBack)133             {134                 if (context.TraceIsEnabled)135                 {136                     this.Trace.Write("aspx.page", "Begin LoadState");137                 }138                 if (EtwTrace.IsTraceEnabled(5, 4))139                 {140                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_VIEWSTATE_ENTER, this._context.WorkerRequest);141                 }142                 this.LoadAllState();143                 if (EtwTrace.IsTraceEnabled(5, 4))144                 {145                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_VIEWSTATE_LEAVE, this._context.WorkerRequest);146                 }147                 if (context.TraceIsEnabled)148                 {149                     this.Trace.Write("aspx.page", "End LoadState");150                     this.Trace.Write("aspx.page", "Begin ProcessPostData");151                 }152                 if (EtwTrace.IsTraceEnabled(5, 4))153                 {154                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_POSTDATA_ENTER, this._context.WorkerRequest);155                 }156                 this.ProcessPostData(this._requestValueCollection, true);157                 if (EtwTrace.IsTraceEnabled(5, 4))158                 {159                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_POSTDATA_LEAVE, this._context.WorkerRequest);160                 }161                 if (context.TraceIsEnabled)162                 {163                     this.Trace.Write("aspx.page", "End ProcessPostData");164                 }165             }166             if (context.TraceIsEnabled)167             {168                 this.Trace.Write("aspx.page", "Begin PreLoad");169             }170             this.OnPreLoad(EventArgs.Empty);171             if (context.TraceIsEnabled)172             {173                 this.Trace.Write("aspx.page", "End PreLoad");174             }175             if (context.TraceIsEnabled)176             {177                 this.Trace.Write("aspx.page", "Begin Load");178             }179             if (EtwTrace.IsTraceEnabled(5, 4))180             {181                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_ENTER, this._context.WorkerRequest);182             }183             this.LoadRecursive();184             if (EtwTrace.IsTraceEnabled(5, 4))185             {186                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_LEAVE, this._context.WorkerRequest);187             }188             if (context.TraceIsEnabled)189             {190                 this.Trace.Write("aspx.page", "End Load");191             }192             if (this.IsPostBack)193             {194                 if (context.TraceIsEnabled)195                 {196                     this.Trace.Write("aspx.page", "Begin ProcessPostData Second Try");197                 }198                 this.ProcessPostData(this._leftoverPostData, false);199                 if (context.TraceIsEnabled)200                 {201                     this.Trace.Write("aspx.page", "End ProcessPostData Second Try");202                     this.Trace.Write("aspx.page", "Begin Raise ChangedEvents");203                 }204                 if (EtwTrace.IsTraceEnabled(5, 4))205                 {206                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_POST_DATA_CHANGED_ENTER, this._context.WorkerRequest);207                 }208                 this.RaiseChangedEvents();209                 if (EtwTrace.IsTraceEnabled(5, 4))210                 {211                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_POST_DATA_CHANGED_LEAVE, this._context.WorkerRequest);212                 }213                 if (context.TraceIsEnabled)214                 {215                     this.Trace.Write("aspx.page", "End Raise ChangedEvents");216                     this.Trace.Write("aspx.page", "Begin Raise PostBackEvent");217                 }218                 if (EtwTrace.IsTraceEnabled(5, 4))219                 {220                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RAISE_POSTBACK_ENTER, this._context.WorkerRequest);221                 }222                 this.RaisePostBackEvent(this._requestValueCollection);223                 if (EtwTrace.IsTraceEnabled(5, 4))224                 {225                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RAISE_POSTBACK_LEAVE, this._context.WorkerRequest);226                 }227                 if (context.TraceIsEnabled)228                 {229                     this.Trace.Write("aspx.page", "End Raise PostBackEvent");230                 }231             }232             if (context.TraceIsEnabled)233             {234                 this.Trace.Write("aspx.page", "Begin LoadComplete");235             }236             this.OnLoadComplete(EventArgs.Empty);237             if (context.TraceIsEnabled)238             {239                 this.Trace.Write("aspx.page", "End LoadComplete");240             }241             if (this.IsPostBack && this.IsCallback)242             {243                 this.PrepareCallback(callbackControlID);244             }245             else if (!this.IsCrossPagePostBack)246             {247                 if (context.TraceIsEnabled)248                 {249                     this.Trace.Write("aspx.page", "Begin PreRender");250                 }251                 if (EtwTrace.IsTraceEnabled(5, 4))252                 {253                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_RENDER_ENTER, this._context.WorkerRequest);254                 }255                 this.PreRenderRecursiveInternal();256                 if (EtwTrace.IsTraceEnabled(5, 4))257                 {258                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_RENDER_LEAVE, this._context.WorkerRequest);259                 }260                 if (context.TraceIsEnabled)261                 {262                     this.Trace.Write("aspx.page", "End PreRender");263                 }264             }265         }266         if ((this._legacyAsyncInfo == null) || this._legacyAsyncInfo.CallerIsBlocking)267         {268             this.ExecuteRegisteredAsyncTasks();269         }270         this.ValidateRawUrlIfRequired();271         if (includeStagesAfterAsyncPoint)272         {273             if (this.IsCallback)274             {275                 this.RenderCallback();276             }277             else if (!this.IsCrossPagePostBack)278             {279                 if (context.TraceIsEnabled)280                 {281                     this.Trace.Write("aspx.page", "Begin PreRenderComplete");282                 }283                 this.PerformPreRenderComplete();284                 if (context.TraceIsEnabled)285                 {286                     this.Trace.Write("aspx.page", "End PreRenderComplete");287                 }288                 if (context.TraceIsEnabled)289                 {290                     this.BuildPageProfileTree(this.EnableViewState);291                     this.Trace.Write("aspx.page", "Begin SaveState");292                 }293                 if (EtwTrace.IsTraceEnabled(5, 4))294                 {295                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_SAVE_VIEWSTATE_ENTER, this._context.WorkerRequest);296                 }297                 this.SaveAllState();298                 if (EtwTrace.IsTraceEnabled(5, 4))299                 {300                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_SAVE_VIEWSTATE_LEAVE, this._context.WorkerRequest);301                 }302                 if (context.TraceIsEnabled)303                 {304                     this.Trace.Write("aspx.page", "End SaveState");305                     this.Trace.Write("aspx.page", "Begin SaveStateComplete");306                 }307                 this.OnSaveStateComplete(EventArgs.Empty);308                 if (context.TraceIsEnabled)309                 {310                     this.Trace.Write("aspx.page", "End SaveStateComplete");311                     this.Trace.Write("aspx.page", "Begin Render");312                 }313                 if (EtwTrace.IsTraceEnabled(5, 4))314                 {315                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RENDER_ENTER, this._context.WorkerRequest);316                 }317                 if (str != null)318                 {319                     this.ExportWebPart(str);320                 }321                 else322                 {323                     this.RenderControl(this.CreateHtmlTextWriter(this.Response.Output));324                 }325                 if (EtwTrace.IsTraceEnabled(5, 4))326                 {327                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RENDER_LEAVE, this._context.WorkerRequest);328                 }329                 if (context.TraceIsEnabled)330                 {331                     this.Trace.Write("aspx.page", "End Render");332                 }333                 this.CheckRemainingAsyncTasks(false);334             }335         }336     }337     catch (ThreadAbortException exception1)338     {339         HttpApplication.CancelModuleException exceptionState = exception1.ExceptionState as HttpApplication.CancelModuleException;340         if ((((includeStagesBeforeAsyncPoint & includeStagesAfterAsyncPoint) && (this._context.Handler == this)) && ((this._context.ApplicationInstance != null) && (exceptionState != null))) && !exceptionState.Timeout)341         {342             this._context.ApplicationInstance.CompleteRequest();343             ThreadResetAbortWithAssert();344         }345         else346         {347             this.CheckRemainingAsyncTasks(true);348             throw;349         }350     }351     catch (ConfigurationException)352     {353         throw;354     }355     catch (Exception exception2)356     {357         PerfCounters.IncrementCounter(AppPerfCounter.ERRORS_DURING_REQUEST);358         PerfCounters.IncrementCounter(AppPerfCounter.ERRORS_TOTAL);359         if (!this.HandleError(exception2))360         {361             throw;362         }363     }364 }365 366  367 368  369   private void ProcessRequestMain(bool includeStagesBeforeAsyncPoint, bool includeStagesAfterAsyncPoint)370 {371     try372     {373         HttpContext context = this.Context;374         string str = null;375         if (includeStagesBeforeAsyncPoint)376         {377             if (this.IsInAspCompatMode)378             {379                 AspCompatApplicationStep.OnPageStartSessionObjects();380             }381             if (this.PageAdapter != null)382             {383                 this._requestValueCollection = this.PageAdapter.DeterminePostBackMode();384                 if (this._requestValueCollection != null)385                 {386                     this._unvalidatedRequestValueCollection = this.PageAdapter.DeterminePostBackModeUnvalidated();387                 }388             }389             else390             {391                 this._requestValueCollection = this.DeterminePostBackMode();392                 if (this._requestValueCollection != null)393                 {394                     this._unvalidatedRequestValueCollection = this.DeterminePostBackModeUnvalidated();395                 }396             }397             string callbackControlID = string.Empty;398             if (this.DetermineIsExportingWebPart())399             {400                 if (!RuntimeConfig.GetAppConfig().WebParts.EnableExport)401                 {402                     throw new InvalidOperationException(SR.GetString("WebPartExportHandler_DisabledExportHandler"));403                 }404                 str = this.Request.QueryString["webPart"];405                 if (string.IsNullOrEmpty(str))406                 {407                     throw new InvalidOperationException(SR.GetString("WebPartExportHandler_InvalidArgument"));408                 }409                 if (string.Equals(this.Request.QueryString["scope"], "shared", StringComparison.OrdinalIgnoreCase))410                 {411                     this._pageFlags.Set(4);412                 }413                 string str3 = this.Request.QueryString["query"];414                 if (str3 == null)415                 {416                     str3 = string.Empty;417                 }418                 this.Request.QueryStringText = str3;419                 context.Trace.IsEnabled = false;420             }421             if (this._requestValueCollection != null)422             {423                 if (this._requestValueCollection["__VIEWSTATEENCRYPTED"] != null)424                 {425                     this.ContainsEncryptedViewState = true;426                 }427                 callbackControlID = this._requestValueCollection["__CALLBACKID"];428                 if ((callbackControlID != null) && (this._request.HttpVerb == HttpVerb.POST))429                 {430                     this._isCallback = true;431                 }432                 else if (!this.IsCrossPagePostBack)433                 {434                     VirtualPath path = null;435                     if (this._requestValueCollection["__PREVIOUSPAGE"] != null)436                     {437                         try438                         {439                             path = VirtualPath.CreateNonRelativeAllowNull(DecryptString(this._requestValueCollection["__PREVIOUSPAGE"], Purpose.WebForms_Page_PreviousPageID));440                         }441                         catch442                         {443                             this._pageFlags[8] = true;444                         }445                         if ((path != null) && (path != this.Request.CurrentExecutionFilePathObject))446                         {447                             this._pageFlags[8] = true;448                             this._previousPagePath = path;449                         }450                     }451                 }452             }453             if (this.MaintainScrollPositionOnPostBack)454             {455                 this.LoadScrollPosition();456             }457             if (context.TraceIsEnabled)458             {459                 this.Trace.Write("aspx.page", "Begin PreInit");460             }461             if (EtwTrace.IsTraceEnabled(5, 4))462             {463                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_INIT_ENTER, this._context.WorkerRequest);464             }465             this.PerformPreInit();466             if (EtwTrace.IsTraceEnabled(5, 4))467             {468                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_INIT_LEAVE, this._context.WorkerRequest);469             }470             if (context.TraceIsEnabled)471             {472                 this.Trace.Write("aspx.page", "End PreInit");473             }474             if (context.TraceIsEnabled)475             {476                 this.Trace.Write("aspx.page", "Begin Init");477             }478             if (EtwTrace.IsTraceEnabled(5, 4))479             {480                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_INIT_ENTER, this._context.WorkerRequest);481             }482             this.InitRecursive(null);483             if (EtwTrace.IsTraceEnabled(5, 4))484             {485                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_INIT_LEAVE, this._context.WorkerRequest);486             }487             if (context.TraceIsEnabled)488             {489                 this.Trace.Write("aspx.page", "End Init");490             }491             if (context.TraceIsEnabled)492             {493                 this.Trace.Write("aspx.page", "Begin InitComplete");494             }495             this.OnInitComplete(EventArgs.Empty);496             if (context.TraceIsEnabled)497             {498                 this.Trace.Write("aspx.page", "End InitComplete");499             }500             if (this.IsPostBack)501             {502                 if (context.TraceIsEnabled)503                 {504                     this.Trace.Write("aspx.page", "Begin LoadState");505                 }506                 if (EtwTrace.IsTraceEnabled(5, 4))507                 {508                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_VIEWSTATE_ENTER, this._context.WorkerRequest);509                 }510                 this.LoadAllState();511                 if (EtwTrace.IsTraceEnabled(5, 4))512                 {513                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_VIEWSTATE_LEAVE, this._context.WorkerRequest);514                 }515                 if (context.TraceIsEnabled)516                 {517                     this.Trace.Write("aspx.page", "End LoadState");518                     this.Trace.Write("aspx.page", "Begin ProcessPostData");519                 }520                 if (EtwTrace.IsTraceEnabled(5, 4))521                 {522                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_POSTDATA_ENTER, this._context.WorkerRequest);523                 }524                 this.ProcessPostData(this._requestValueCollection, true);525                 if (EtwTrace.IsTraceEnabled(5, 4))526                 {527                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_POSTDATA_LEAVE, this._context.WorkerRequest);528                 }529                 if (context.TraceIsEnabled)530                 {531                     this.Trace.Write("aspx.page", "End ProcessPostData");532                 }533             }534             if (context.TraceIsEnabled)535             {536                 this.Trace.Write("aspx.page", "Begin PreLoad");537             }538             this.OnPreLoad(EventArgs.Empty);539             if (context.TraceIsEnabled)540             {541                 this.Trace.Write("aspx.page", "End PreLoad");542             }543             if (context.TraceIsEnabled)544             {545                 this.Trace.Write("aspx.page", "Begin Load");546             }547             if (EtwTrace.IsTraceEnabled(5, 4))548             {549                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_ENTER, this._context.WorkerRequest);550             }551             this.LoadRecursive();552             if (EtwTrace.IsTraceEnabled(5, 4))553             {554                 EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_LOAD_LEAVE, this._context.WorkerRequest);555             }556             if (context.TraceIsEnabled)557             {558                 this.Trace.Write("aspx.page", "End Load");559             }560             if (this.IsPostBack)561             {562                 if (context.TraceIsEnabled)563                 {564                     this.Trace.Write("aspx.page", "Begin ProcessPostData Second Try");565                 }566                 this.ProcessPostData(this._leftoverPostData, false);567                 if (context.TraceIsEnabled)568                 {569                     this.Trace.Write("aspx.page", "End ProcessPostData Second Try");570                     this.Trace.Write("aspx.page", "Begin Raise ChangedEvents");571                 }572                 if (EtwTrace.IsTraceEnabled(5, 4))573                 {574                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_POST_DATA_CHANGED_ENTER, this._context.WorkerRequest);575                 }576                 this.RaiseChangedEvents();577                 if (EtwTrace.IsTraceEnabled(5, 4))578                 {579                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_POST_DATA_CHANGED_LEAVE, this._context.WorkerRequest);580                 }581                 if (context.TraceIsEnabled)582                 {583                     this.Trace.Write("aspx.page", "End Raise ChangedEvents");584                     this.Trace.Write("aspx.page", "Begin Raise PostBackEvent");585                 }586                 if (EtwTrace.IsTraceEnabled(5, 4))587                 {588                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RAISE_POSTBACK_ENTER, this._context.WorkerRequest);589                 }590                 this.RaisePostBackEvent(this._requestValueCollection);591                 if (EtwTrace.IsTraceEnabled(5, 4))592                 {593                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RAISE_POSTBACK_LEAVE, this._context.WorkerRequest);594                 }595                 if (context.TraceIsEnabled)596                 {597                     this.Trace.Write("aspx.page", "End Raise PostBackEvent");598                 }599             }600             if (context.TraceIsEnabled)601             {602                 this.Trace.Write("aspx.page", "Begin LoadComplete");603             }604             this.OnLoadComplete(EventArgs.Empty);605             if (context.TraceIsEnabled)606             {607                 this.Trace.Write("aspx.page", "End LoadComplete");608             }609             if (this.IsPostBack && this.IsCallback)610             {611                 this.PrepareCallback(callbackControlID);612             }613             else if (!this.IsCrossPagePostBack)614             {615                 if (context.TraceIsEnabled)616                 {617                     this.Trace.Write("aspx.page", "Begin PreRender");618                 }619                 if (EtwTrace.IsTraceEnabled(5, 4))620                 {621                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_RENDER_ENTER, this._context.WorkerRequest);622                 }623                 this.PreRenderRecursiveInternal();624                 if (EtwTrace.IsTraceEnabled(5, 4))625                 {626                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_PRE_RENDER_LEAVE, this._context.WorkerRequest);627                 }628                 if (context.TraceIsEnabled)629                 {630                     this.Trace.Write("aspx.page", "End PreRender");631                 }632             }633         }634         if ((this._legacyAsyncInfo == null) || this._legacyAsyncInfo.CallerIsBlocking)635         {636             this.ExecuteRegisteredAsyncTasks();637         }638         this.ValidateRawUrlIfRequired();639         if (includeStagesAfterAsyncPoint)640         {641             if (this.IsCallback)642             {643                 this.RenderCallback();644             }645             else if (!this.IsCrossPagePostBack)646             {647                 if (context.TraceIsEnabled)648                 {649                     this.Trace.Write("aspx.page", "Begin PreRenderComplete");650                 }651                 this.PerformPreRenderComplete();652                 if (context.TraceIsEnabled)653                 {654                     this.Trace.Write("aspx.page", "End PreRenderComplete");655                 }656                 if (context.TraceIsEnabled)657                 {658                     this.BuildPageProfileTree(this.EnableViewState);659                     this.Trace.Write("aspx.page", "Begin SaveState");660                 }661                 if (EtwTrace.IsTraceEnabled(5, 4))662                 {663                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_SAVE_VIEWSTATE_ENTER, this._context.WorkerRequest);664                 }665                 this.SaveAllState();666                 if (EtwTrace.IsTraceEnabled(5, 4))667                 {668                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_SAVE_VIEWSTATE_LEAVE, this._context.WorkerRequest);669                 }670                 if (context.TraceIsEnabled)671                 {672                     this.Trace.Write("aspx.page", "End SaveState");673                     this.Trace.Write("aspx.page", "Begin SaveStateComplete");674                 }675                 this.OnSaveStateComplete(EventArgs.Empty);676                 if (context.TraceIsEnabled)677                 {678                     this.Trace.Write("aspx.page", "End SaveStateComplete");679                     this.Trace.Write("aspx.page", "Begin Render");680                 }681                 if (EtwTrace.IsTraceEnabled(5, 4))682                 {683                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RENDER_ENTER, this._context.WorkerRequest);684                 }685                 if (str != null)686                 {687                     this.ExportWebPart(str);688                 }689                 else690                 {691                     this.RenderControl(this.CreateHtmlTextWriter(this.Response.Output));692                 }693                 if (EtwTrace.IsTraceEnabled(5, 4))694                 {695                     EtwTrace.Trace(EtwTraceType.ETW_TYPE_PAGE_RENDER_LEAVE, this._context.WorkerRequest);696                 }697                 if (context.TraceIsEnabled)698                 {699                     this.Trace.Write("aspx.page", "End Render");700                 }701                 this.CheckRemainingAsyncTasks(false);702             }703         }704     }705     catch (ThreadAbortException exception1)706     {707         HttpApplication.CancelModuleException exceptionState = exception1.ExceptionState as HttpApplication.CancelModuleException;708         if ((((includeStagesBeforeAsyncPoint & includeStagesAfterAsyncPoint) && (this._context.Handler == this)) && ((this._context.ApplicationInstance != null) && (exceptionState != null))) && !exceptionState.Timeout)709         {710             this._context.ApplicationInstance.CompleteRequest();711             ThreadResetAbortWithAssert();712         }713         else714         {715             this.CheckRemainingAsyncTasks(true);716             throw;717         }718     }719     catch (ConfigurationException)720     {721         throw;722     }723     catch (Exception exception2)724     {725         PerfCounters.IncrementCounter(AppPerfCounter.ERRORS_DURING_REQUEST);726         PerfCounters.IncrementCounter(AppPerfCounter.ERRORS_TOTAL);727         if (!this.HandleError(exception2))728         {729             throw;730         }731     }732 }733 734