ASP.Net下的HttpModule是基于事件的处理模型，这使得我们在选择事件监听和处理的时候有更多选择。下面是对HttpModule有关事件被触发的监测：

有关代码如下

using System;using System.Data;using System.Configuration;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;using System.Web.SessionState;using System.Threading;/// ///EventTest 的摘要说明/// public class EventTest : IHttpModule, IRequiresSessionState{    public EventTest()    {        //        //TODO: 在此处添加构造函数逻辑        //    }    void IHttpModule.Dispose()    {        return;    }    void IHttpModule.Init(HttpApplication App)    {        App.AcquireRequestState += new EventHandler(AcquireRequestState);        App.BeginRequest += new EventHandler(BeginRequest);        App.AuthenticateRequest += new EventHandler(AuthenticateRequest);        App.AuthorizeRequest += new EventHandler(AuthorizeRequest);        App.Disposed += new EventHandler(Disposed);        App.EndRequest += new EventHandler(EndRequest);        App.Error += new EventHandler(Error);        //App.MapRequestHandler += new EventHandler(MapRequestHandler);        App.PostAcquireRequestState += new EventHandler(PostAcquireRequestState);        App.PostAuthenticateRequest += new EventHandler(PostAuthenticateRequest);        App.PostAuthorizeRequest += new EventHandler(PostAuthorizeRequest);        //App.PostLogRequest += new EventHandler(PostLogRequest);        App.PostMapRequestHandler += new EventHandler(PostMapRequestHandler);        App.PostReleaseRequestState += new EventHandler(PostReleaseRequestState);        App.PostRequestHandlerExecute += new EventHandler(PostRequestHandlerExecute);        App.PostResolveRequestCache += new EventHandler(PostResolveRequestCache);        App.PostUpdateRequestCache += new EventHandler(PostUpdateRequestCache);        App.PreRequestHandlerExecute += new EventHandler(PreRequestHandlerExecute);        App.PreSendRequestHeaders += new EventHandler(PreSendRequestHeaders);        App.PreSendRequestContent += new EventHandler(PreSendRequestContent);        App.ReleaseRequestState += new EventHandler(ReleaseRequestState);        App.ResolveRequestCache += new EventHandler(ResolveRequestCache);        App.UpdateRequestCache += new EventHandler(UpdateRequestCache);    }    private void BeginRequest(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：BeginRequest（执行Http请求管线链中第一个事件时发生）");    }    private void AcquireRequestState(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：AcquireRequestState(与当前建立会话时发生)");        if (context.Session["T"] != null)        {            response.Write(" + " + context.Session["T"].ToString());        }        else        {            response.Write(" Session未收到!");        }    }    private void AuthenticateRequest(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：AuthenticateRequest(安全模块建立用户标记时发生)");    }    private void AuthorizeRequest(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：AuthorizeRequest(安全模块验证用户授权时发生)");    }    private void Disposed(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：Disposed(释放应用时发生)");    }    private void EndRequest(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：EndRequest(执行Http请求管线链中最后一个事件时发生)");    }    private void Error(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + Error(Error事件时发生)");    }    private void PostAcquireRequestState(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostAcquireRequestState(已经获得当前请求状态时发生)");        if (context.Session["T"] != null)        {            response.Write(" + " + context.Session["T"].ToString());        }        else        {            response.Write(" Session未收到!");        }    }    private void PostAuthenticateRequest(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostAuthenticateRequest(已建立用户标识时发生)");    }    private void PostAuthorizeRequest(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostAuthorizeRequest(当前请求的用户已获得授权时发生)");    }    private void PostMapRequestHandler(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostMapRequestHandler(当前请求事件映射到相应事件后发生)");    }    private void PostReleaseRequestState(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + PostReleaseRequestState(完成请求事件并且请求状态已存储时发生)");    }    private void PostRequestHandlerExecute(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostRequestHandlerExecute(ASP.Net事件执行完毕时发生)");    }    private void PostResolveRequestCache(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostResolveRequestCache(跳过当前请求并接受来自缓存数据时发生)");    }    private void PostUpdateRequestCache(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PostUpdateRequestCache(事件缓存被更新时发生)");    }    private void PreRequestHandlerExecute(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PreRequestHandlerExecute(页面事件执行前发生)");        if (context.Session["T"] != null)        {            response.Write(" + " + context.Session["T"].ToString());        }        else        {            response.Write(" Session未收到!");        }    }    private void PreSendRequestContent(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        //response.Write("" + time + "  + IHttpModule：PreSendRequestContent(向客户端发送内容之前发生)");    }    private void PreSendRequestHeaders(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：PreSendRequestHeaders(向客户端发送HttP头之前发生)");    }    private void ReleaseRequestState(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：ReleaseRequestState(事件执行完成之后状态处理)");    }    private void ResolveRequestCache(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：ResolveRequestCache(从缓存中发生数据请求时)");    }    private void UpdateRequestCache(object sender, EventArgs e)    {        HttpApplication application = (HttpApplication)sender;        HttpContext context = application.Context;        HttpRequest request = application.Request;        HttpResponse response = application.Response;        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        response.Write("" + time + "  + IHttpModule：UpdateRequestCache(时间执行完毕，为缓存新的事件准备)");    }}

需要在web.Config加入

任意Page的代码（aspx）

protected void Page_Load(object sender, EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_Load");    }    protected void TextBox1_TextChanged(object sender, EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：TextBox1_TextChanged");        Label1.Text = TextBox1.Text;    }    protected void TextBox2_TextChanged(object sender, EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：TextBox2_TextChanged");        Label2.Text = TextBox2.Text;    }    private void Page_LoadComplete(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_LoadComplete");    }    private void Page_Unload(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        //Response.Write("" + time + "  + Page_Unload");    }    private void Page_PreInit(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_PreInit");    }    private void Page_Init(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Session["T"] = "来自Page级：Page_Init" + time;        Response.Write("" + time + "  + Page：Page_Init");    }    private void Page_InitComplete(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_InitComplete");    }    private void Page_PreLoad(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_PreLoad");    }    private void Page_PreRender(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_PreRender");    }    private void Page_PreRenderComplete(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_PreRenderComplete");    }    private void Page_SaveStateComplete(object sender, System.EventArgs e)    {        string time = DateTime.Now.ToString() + ":" + DateTime.Now.Millisecond.ToString("000");        Response.Write("" + time + "  + Page：Page_SaveStateComplete");    }

当Page（aspx）页面事件被加载（首次）被加载后的信息

2009-11-22 18:02:35:828 + IHttpModule：BeginRequest（执行Http请求管线链中第一个事件时发生）2009-11-22 18:02:35:828 + IHttpModule：AuthenticateRequest(安全模块建立用户标记时发生)2009-11-22 18:02:35:828 + IHttpModule：PostAuthenticateRequest(已建立用户标识时发生)2009-11-22 18:02:35:828 + IHttpModule：AuthorizeRequest(安全模块验证用户授权时发生)2009-11-22 18:02:35:828 + IHttpModule：PostAuthorizeRequest(当前请求的用户已获得授权时发生)2009-11-22 18:02:35:828 + IHttpModule：ResolveRequestCache(从缓存中发生数据请求时)2009-11-22 18:02:35:828 + IHttpModule：PostResolveRequestCache(跳过当前请求并接受来自缓存数据时发生)2009-11-22 18:02:35:859 + IHttpModule：PostMapRequestHandler(当前请求事件映射到相应事件后发生)2009-11-22 18:02:35:859 + IHttpModule：AcquireRequestState(与当前建立会话时发生) Session未收到!2009-11-22 18:02:35:859 + IHttpModule：PostAcquireRequestState(已经获得当前请求状态时发生) Session未收到!2009-11-22 18:02:35:859 + IHttpModule：PreRequestHandlerExecute(页面事件执行前发生) Session未收到!2009-11-22 18:02:35:875 + Page：Page_PreInit2009-11-22 18:02:35:875 + Page：Page_Init2009-11-22 18:02:35:875 + Page：Page_InitComplete2009-11-22 18:02:35:875 + Page：Page_PreLoad2009-11-22 18:02:35:875 + Page：Page_Load2009-11-22 18:02:35:875 + Page：Page_LoadComplete2009-11-22 18:02:35:875 + Page：Page_PreRender2009-11-22 18:02:35:875 + Page：Page_PreRenderComplete2009-11-22 18:02:35:953 + Page：Page_SaveStateCompleteLabel1（aspx页面的）Label2（aspx页面的）2009-11-22 18:02:35:953 + IHttpModule：PostRequestHandlerExecute(ASP.Net事件执行完毕时发生)2009-11-22 18:02:35:953 + IHttpModule：ReleaseRequestState(事件执行完成之后状态处理)2009-11-22 18:02:35:953 + PostReleaseRequestState(完成请求事件并且请求状态已存储时发生)2009-11-22 18:02:35:953 + IHttpModule：UpdateRequestCache(时间执行完毕，为缓存新的事件准备)2009-11-22 18:02:35:953 + IHttpModule：PostUpdateRequestCache(事件缓存被更新时发生)2009-11-22 18:02:35:953 + IHttpModule：EndRequest(执行Http请求管线链中最后一个事件时发生)2009-11-22 18:02:35:953 + IHttpModule：PreSendRequestHeaders(向客户端发送HttP头之前发生)

注意，想使用Session时，必须在AcquireRequestState，PostAcquireRequestState以及PreRequestHandlerExecute事件中.

页面事件被触发

2009-11-22 18:30:05:843 + IHttpModule：BeginRequest（执行Http请求管线链中第一个事件时发生）2009-11-22 18:30:05:843 + IHttpModule：AuthenticateRequest(安全模块建立用户标记时发生)2009-11-22 18:30:05:843 + IHttpModule：PostAuthenticateRequest(已建立用户标识时发生)2009-11-22 18:30:05:843 + IHttpModule：AuthorizeRequest(安全模块验证用户授权时发生)2009-11-22 18:30:05:843 + IHttpModule：PostAuthorizeRequest(当前请求的用户已获得授权时发生)2009-11-22 18:30:05:843 + IHttpModule：ResolveRequestCache(从缓存中发生数据请求时)2009-11-22 18:30:05:843 + IHttpModule：PostResolveRequestCache(跳过当前请求并接受来自缓存数据时发生)2009-11-22 18:30:05:843 + IHttpModule：PostMapRequestHandler(当前请求事件映射到相应事件后发生)2009-11-22 18:30:05:843 + IHttpModule：AcquireRequestState(与当前建立会话时发生) + 来自Page级：Page_Init2009-11-22 18:30:03:4062009-11-22 18:30:05:843 + IHttpModule：PostAcquireRequestState(已经获得当前请求状态时发生) + 来自Page级：Page_Init2009-11-22 18:30:03:4062009-11-22 18:30:05:843 + IHttpModule：PreRequestHandlerExecute(页面事件执行前发生) + 来自Page级：Page_Init2009-11-22 18:30:03:4062009-11-22 18:30:05:843 + Page：Page_PreInit2009-11-22 18:30:05:843 + Page：Page_Init2009-11-22 18:30:05:843 + Page：Page_InitComplete2009-11-22 18:30:05:843 + Page：Page_PreLoad2009-11-22 18:30:05:843 + Page：Page_Load2009-11-22 18:30:05:843 + Page：TextBox1_TextChanged2009-11-22 18:30:05:843 + Page：Page_LoadComplete2009-11-22 18:30:05:843 + Page：Page_PreRender2009-11-22 18:30:05:843 + Page：Page_PreRenderComplete2009-11-22 18:30:05:843 + Page：Page_SaveStateCompleteaspx 页面信息2009-11-22 18:30:05:843 + IHttpModule：PostRequestHandlerExecute(ASP.Net事件执行完毕时发生)2009-11-22 18:30:05:843 + IHttpModule：ReleaseRequestState(事件执行完成之后状态处理)2009-11-22 18:30:05:843 + PostReleaseRequestState(完成请求事件并且请求状态已存储时发生)2009-11-22 18:30:05:843 + IHttpModule：UpdateRequestCache(时间执行完毕，为缓存新的事件准备)2009-11-22 18:30:05:843 + IHttpModule：PostUpdateRequestCache(事件缓存被更新时发生)2009-11-22 18:30:05:843 + IHttpModule：EndRequest(执行Http请求管线链中最后一个事件时发生)2009-11-22 18:30:05:843 + IHttpModule：PreSendRequestHeaders(向客户端发送HttP头之前发生)

以下为摘录,用于加深事件模型的理解

Page 执行中将按照如下顺序激活事件：Page.PreInitPage.InitPage.InitComplitePage.PreLoadPage.LoadPage.LoadCompletePage.PreRenderPage.PreRenderComplete如果页面从令一个页面继承，如BasePage:System.Web.UI.Page，在BasePage中做了一些扩展，如权限检查，而其他页面从BasePage继承，则BasePage和最终Page的事件激活顺序是：UI.PreInitPage.PreInitUI.InitPage.InitUI.InitComplitePage.InitCompliteUI.PreLoadPage.PreLoadUI.LoadPage.LoadUI.LoadCompletePage.LoadCompleteUI.PreRenderPage.PreRenderUI.PreRenderCompletePage.PreRenderComplete如果使用了MasterPage，则MasterPage中的事件和ContentPage中的事件按照下面顺序激活：ContentPage.PreInitMaster.InitContentPage.InitContentPage.InitCompliteContentPage.PreLoadContentPage.LoadMaster.LoadContentPage.LoadCompleteContentPage.PreRenderMaster.PreRenderContentPage.PreRenderComplete更进一步，如果ContentPage继承BasePage，那么，各事件的执行顺序将变成：UI.PreInitContentPage.PreInitMaster.InitUI.InitContentPage.InitUI.InitCompliteContentPage.InitCompliteUI.PreLoadContentPage.PreLoadUI.LoadContentPage.LoadMaster.LoadUI.LoadCompleteContentPage.LoadCompleteUI.PreRenderContentPage.PreRenderMaster.PreRenderUI.PreRenderCompleteContentPage.PreRenderComplete

MasterPage	UserControlOnTop	Page	UserControlInPage	UserControlOnButtom
	Init
			Init
				Init
Init
		Init
		Load
Load
	Load
			Lod
				Load
ControlEvents	ControlEvents	ControlEvents	ControlEvents	ControlEvents
		PreRender
PreRender
	PreRender
			PreRender
				PreRender
	UnLoad
			UnLoad
				UnLoad
UnLoad
		UnLoad