asp.net Page事件處理管線

我們知道頁面就是一個處理常式，裡面的實現非常複雜，網上也有很多資料講到asp.net的管道處理，有關page的事件處理也不少；這裡我就page的事件處理結果

這裡的總結來至asp.net本質論。我們也知道page的處理都集中在一個ProcessRequest方法中，該方法最終主要還是調用ProcessRequestMain方法。其主要實現如下：

private void ProcessRequestMain(bool includeStagesBeforeAsyncPoint, bool includeStagesAfterAsyncPoint){    try    {        HttpContext context = this.Context;        string str = null;        if (includeStagesBeforeAsyncPoint)        {            if (this.IsInAspCompatMode)            {                AspCompatApplicationStep.OnPageStartSessionObjects();            }            if (this.PageAdapter != null)            {                this._requestValueCollection = this.PageAdapter.DeterminePostBackMode();                if (this._requestValueCollection != null)                {                    this._unvalidatedRequestValueCollection = this.PageAdapter.DeterminePostBackModeUnvalidated();                }            }            else            {                this._requestValueCollection = this.DeterminePostBackMode();                if (this._requestValueCollection != null)                {                    this._unvalidatedRequestValueCollection = this.DeterminePostBackModeUnvalidated();                }            }            string callbackControlID = string.Empty;            if (this.DetermineIsExportingWebPart())            {                if (!RuntimeConfig.GetAppConfig().WebParts.EnableExport)                {                    throw new InvalidOperationException(SR.GetString("WebPartExportHandler_DisabledExportHandler"));                }                str = this.Request.QueryString["webPart"];                if (string.IsNullOrEmpty(str))                {                    throw new InvalidOperationException(SR.GetString("WebPartExportHandler_InvalidArgument"));                }                if (string.Equals(this.Request.QueryString["scope"], "shared", StringComparison.OrdinalIgnoreCase))                {                    this._pageFlags.Set(4);                }                string str3 = this.Request.QueryString["query"];                if (str3 == null)                {                    str3 = string.Empty;                }                this.Request.QueryStringText = str3;                context.Trace.IsEnabled = false;            }            if (this._requestValueCollection != null)            {                if (this._requestValueCollection["__VIEWSTATEENCRYPTED"] != null)                {                    this.ContainsEncryptedViewState = true;                }                callbackControlID = this._requestValueCollection["__CALLBACKID"];                if ((callbackControlID != null) && (this._request.HttpVerb == HttpVerb.POST))                {                    this._isCallback = true;                }                else if (!this.IsCrossPagePostBack)                {                    VirtualPath path = null;                    if (this._requestValueCollection["__PREVIOUSPAGE"] != null)                    {                        try                        {                            path = VirtualPath.CreateNonRelativeAllowNull(DecryptString(this._requestValueCollection["__PREVIOUSPAGE"], Purpose.WebForms_Page_PreviousPageID));                        }                        catch                        {                            this._pageFlags[8] = true;                        }                        if ((path != null) && (path != this.Request.CurrentExecutionFilePathObject))                        {                            this._pageFlags[8] = true;                            this._previousPagePath = path;                        }                    }                }            }            if (this.MaintainScrollPositionOnPostBack)            {                this.LoadScrollPosition();            }            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "Begin PreInit");            }            this.PerformPreInit();            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "End PreInit");            }            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "Begin Init");            }            this.InitRecursive(null);            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "End Init");            }            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "Begin InitComplete");            }            this.OnInitComplete(EventArgs.Empty);            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "End InitComplete");            }            if (this.IsPostBack)            {                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "Begin LoadState");                }                this.LoadAllState();                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End LoadState");                    this.Trace.Write("aspx.page", "Begin ProcessPostData");                }                this.ProcessPostData(this._requestValueCollection, true);                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End ProcessPostData");                }            }            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "Begin PreLoad");            }            this.OnPreLoad(EventArgs.Empty);            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "End PreLoad");            }            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "Begin Load");            }            this.LoadRecursive();            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "End Load");            }            if (this.IsPostBack)            {                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "Begin ProcessPostData Second Try");                }                this.ProcessPostData(this._leftoverPostData, false);                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End ProcessPostData Second Try");                    this.Trace.Write("aspx.page", "Begin Raise ChangedEvents");                }                this.RaiseChangedEvents();                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End Raise ChangedEvents");                    this.Trace.Write("aspx.page", "Begin Raise PostBackEvent");                }                this.RaisePostBackEvent(this._requestValueCollection);                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End Raise PostBackEvent");                }            }            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "Begin LoadComplete");            }            this.OnLoadComplete(EventArgs.Empty);            if (context.TraceIsEnabled)            {                this.Trace.Write("aspx.page", "End LoadComplete");            }            if (this.IsPostBack && this.IsCallback)            {                this.PrepareCallback(callbackControlID);            }            else if (!this.IsCrossPagePostBack)            {                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "Begin PreRender");                }                this.PreRenderRecursiveInternal();                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End PreRender");                }            }        }        if ((this._legacyAsyncInfo == null) || this._legacyAsyncInfo.CallerIsBlocking)        {            this.ExecuteRegisteredAsyncTasks();        }        this.ValidateRawUrlIfRequired();        if (includeStagesAfterAsyncPoint)        {            if (this.IsCallback)            {                this.RenderCallback();            }            else if (!this.IsCrossPagePostBack)            {                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "Begin PreRenderComplete");                }                this.PerformPreRenderComplete();                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End PreRenderComplete");                }                if (context.TraceIsEnabled)                {                    this.BuildPageProfileTree(this.EnableViewState);                    this.Trace.Write("aspx.page", "Begin SaveState");                }                this.SaveAllState();                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End SaveState");                    this.Trace.Write("aspx.page", "Begin SaveStateComplete");                }                this.OnSaveStateComplete(EventArgs.Empty);                if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End SaveStateComplete");                    this.Trace.Write("aspx.page", "Begin Render");                }                if (str != null)                {                    this.ExportWebPart(str);                }                else                {                    this.RenderControl(this.CreateHtmlTextWriter(this.Response.Output));                }                 if (context.TraceIsEnabled)                {                    this.Trace.Write("aspx.page", "End Render");                }                this.CheckRemainingAsyncTasks(false);            }        }    }      catch (ConfigurationException)    {        throw;    }    }

 在這個方法中有兩段代碼比較有意思

  this.OnInitComplete(EventArgs.Empty);

 if (context.TraceIsEnabled)
            {
                this.Trace.Write("aspx.page", "End InitComplete");
            }
            if (this.IsPostBack)
            {
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "Begin LoadState");
                }
                this.LoadAllState();
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "End LoadState");
                    this.Trace.Write("aspx.page", "Begin ProcessPostData");
                }
                this.ProcessPostData(this._requestValueCollection, true);
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "End ProcessPostData");
                }
            }
            if (context.TraceIsEnabled)
            {
                this.Trace.Write("aspx.page", "Begin PreLoad");
            }
            this.OnPreLoad(EventArgs.Empty);

和

 this.LoadRecursive();
            if (context.TraceIsEnabled)
            {
                this.Trace.Write("aspx.page", "End Load");
            }
            if (this.IsPostBack)
            {
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "Begin ProcessPostData Second Try");
                }
                this.ProcessPostData(this._leftoverPostData, false);
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "End ProcessPostData Second Try");
                    this.Trace.Write("aspx.page", "Begin Raise ChangedEvents");
                }
                this.RaiseChangedEvents();
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "End Raise ChangedEvents");
                    this.Trace.Write("aspx.page", "Begin Raise PostBackEvent");
                }
                this.RaisePostBackEvent(this._requestValueCollection);
                if (context.TraceIsEnabled)
                {
                    this.Trace.Write("aspx.page", "End Raise PostBackEvent");
                }
            }
            if (context.TraceIsEnabled)
            {
                this.Trace.Write("aspx.page", "Begin
LoadComplete");
            }
            this.OnLoadComplete(EventArgs.Empty);

整過post過來的請求與get相比就多了這中間一點處理，我們也知道page在處理post請求時需要處理資料的載入IPostBackDataHandler和事件的觸發IPostBackEventHandler.

所以為什麼這回分成兩段就比較好理解了。

有關他們的介紹如下：