【深入ASP.NET原理系列】--ASP.NET頁面生命周期

2019-11-14 14:22:53

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前言

asp.net頁面運行時候，頁面將經歷一個生命周期，在生命周期中將執行一系列的處理步驟。包括初始化、實例化控件、還原和維護狀態、運行時間處理程序代碼以及進行呈現。熟悉頁面生命周期非常重要，這樣我們才能在生命周期的合適階段編寫代碼。如果我們能在寫代碼的時候想著我們現在是在做生命周期的哪一步那將是非常好的。

你可能會說我不清楚還不是一樣寫代碼，反正每次都在Page_load里面寫代碼然后頁面就出來了我管那么多干什么。所謂知其然如果能知其所以然豈不是更吊？我個人認為做ASP.NET B/S開發只要咱們熟悉ASP.NET頁面生命周期，熟悉“請求-處理-響應“模式，對于一時半兒沒有觸及到的細節，等真正遇到那個點再去理解它也是毫不費力的。

幾個代表性的問題

在開始的時候我們先思考幾個問題，看看我們在描述完頁面生命周期的時候，能不能回答上這幾個問題

1.為什么在服務器端能通過this.textbox1.Text獲取到用戶提交過來的數據？

2.在Page_Load中Response.Write("hello")查看生成的html代碼原文件，hello在哪里？為什么？

3.有一個服務器端的按鈕，設置了點擊事件，該點擊事件什么時候執行？是先執行Page_Load事件還是先執行點擊事件？

4.為什么在服務器端通過this.textbox1.Text設置值后，客戶端就能顯示出來？

看過我上一篇博客【深入ASP.NET原理系列】--ASP.NET請求管道、應用程序生命周期、整體運行機制童鞋可能知道，ASP.NET應用程序周期中PReRequestHandlerExecute事件與PostRequestHandlerExecute事件之間就是我們的頁面生命周期了，對于aspx頁面就是一系列的打造頁面控件樹，觸發各種頁面時間，對于一般處理程序ashx就是直接執行咱們開發者寫的ProcessRequest方法了，對于MVC應用程序就是創建控制器工廠，創建控制器對象，調用Action那一套了。

下面主要講述的就是ASP.NET WebForm中的頁面的生命周期了。

我們用反編譯工具查看Page類的ProcessRequest方法可以看見先調用了FrameworkInitialize; FrameworkInitialize里面就是打造了頁面控件樹，然后調用了ProcessRequestMain，就開始了執行整個頁面生命周期了（其實就是調用了一系列的事件方法）（可能部分圖看不見右邊，可在新標簽頁中打開圖片）

1.打造頁面控件樹

FrameworkInitialize內部調用了_buildControlTree（）方法

　　

上圖中左邊是前臺頁面的代碼，右邊是對應 生成的打造控件樹的代碼。中間截取的是生成表單那一部分的代碼。

下面看一張原理圖

瀏覽器的DOM樹是根據Html標簽生成一個C語言的DOM樹，而ASP.NET服務器端是用C#打造的一個控件樹，也是按照DOM結構打造的。本質是一樣。服務器端所有東西都加到頁面對象的控件集合中去了。標簽在服務器端有對應的控件對象的時候就用控件對象，沒有的時候就使用LiteralControl進行封裝。不管是服務器控件還是字符串標簽（沒有runat="server"的標簽）都以控件對象的方式存在前臺頁面類的控件集合里面。好處就是生成前臺頁面的html代碼的時候，只需要遍歷控件集合里面的每一個控件對象的RenderControl方法，每一個控件都會調用自己的Render方法生成對應的Html字符串。那么所有控件的生成的html字符串就還原成一個頁面的html代碼了?！?/span>

2.觸發PerformPreInit事件　

在所有初始化之前初始化了這個事件，這個事件主要是初始化了主題，初始化了母版頁

 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 }

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3.觸發InitRecursive事件

4.觸發LoadAllState()事件

加載頁面狀態解析ViewState，將頁面表單中的ViewState進行反Base64編碼，反序列化，存在頁面的ViewState屬性中

5.觸發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

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主要做了兩件事

1）將表單里提交過來的控件數據設置給頁面對象的控件樹中對應控件的屬性（給前面打造的控件樹里面控件給值），這樣在服務器端就可以拿到客戶端輸入的值了。

2）將表單里面提交過來的值與ViewState中控件原來的值進行比對，不同則表示要觸發該控件的Change 事件，則同時將該控件放到一個集合（看源碼其實就是changedPostDataConsumers）中。在后續執行過程中遍歷改集合依次觸發對應控件的Change事件。

6.觸發LoadRecursive()事件

大名鼎鼎的Page_Load就是在這里執行的。不過是先執行頁面本身的Load事件再執行頁面控件的Load事件哦,這時候前面給控件賦的值,表單提交過來的數據,ViewState等等都可以使用了，IsPostBack的原理就是判斷是否有name為__VIEWSTATE的數據提交過來

7.再次觸發ProcessPostData(this._leftoverPostData, false)事件

這個事件我在網上看了很多人說是將第一次遺漏下來的，第一次執行ProcessPostData沒有涉及到的控件進行處理，但是并沒有說明哪些遺漏下來了。為什么第一次沒處理了？ 最后Google查到是處理我們開發者在頁面的Page_Load方法中添加的控件。在Page_Load中我們可以自己創建控件對象加到頁面對應的“C#DOM樹中“，如：在Page_Load中寫
TextBox txt = new TextBox();txt.ID ="myTxtBox";this.form1.Controls.Add(txt);
這就是把開發者自己創建的控件加在頁面的form1的表單中。當然你也可以加上Change事件了創建控件的時候。執行的還是上面那兩件事了。則回發的時候可以給開發者在Page_Lod中手動創建的控件還原值。

8.觸發RaiseChangedEvents事件

循環遍歷changedPostDataConsumers集合中的所有控件，依次執行控件的非點擊回傳事件，比如文本框的改變事件等

9.觸發RaisePostBackEvent(this._requestValueCollection)事件

執行按鈕點擊回傳事件或者驗證事件，如果有多個按鈕，根據回發過來的按鈕的 name來判斷觸發哪個按鈕的事件，或者觸發該控件的驗證事件

10.觸發PerformPreRenderComplete事件

循環遍歷控件樹中所有的控件，根據每個控件生成對應的Html代碼，把服務器控件渲染成普通的html控件。

11.觸發事件SaveAllState事件

將服務器端ViewState集合中的內容（開發者自己加的數據或控件狀態信息等）序列化然后Base64編碼然后設置到客戶端隱藏域__ViewState中

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

把要發送到客戶端瀏覽器的內容設置到Response.Output，應用程序將它發送 到客戶端瀏覽器。

看到這里不知道大家是否已經可以清晰地回答開篇提到的幾個問題了，其實就是這些事件執行的先后順序，頁面生命周期了。”前人植樹，后人乘涼了"

最后附上生命周期ProcessRequest源碼　　

  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