验证一个ASP.NET应用程序和页面的生命周期的实现代码

如果我们能更好地掌握这样一个过程，那么对单个ASP.NET Page的生命周期也能更好地了解：
下面介绍如何编写一个简单的ASP.NET 页面和一个简单的HttpModule，对MSDN里提到的ASP.NET的生命周期进行验证
1. 首先使用Visual Studio 2010建立一个空的ASP.NET网站 （ASP.NET 4.0）
2. 添加一个Default.aspx，添加三个ASP.NET控件，分别为TextBox，Button和Validator：

　　 
<form id="form1" runat="server"> 
<div> 
<asp:TextBox ID="txtName" runat="server"></asp:TextBox> 
<asp:Button ID="btnSubmit" runat="server" Text="OK" onclick="btnSubmit_Click" /> 
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="Please input your name!" ControlToValidate="txtName" ForeColor="#FF3300"> 
</asp:RequiredFieldValidator> 
</div> 
</form>

3. 添加一个ASP.NEt的App_code文件夹，新建一个类，内容为：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
public class TestClass : IHttpModule 
{ 
HttpApplication httpApp; 
public static List<string> EventList = new List<string>(); 
public TestClass() 
{ 
} 
public void Dispose() 
{ } 
public void Init(HttpApplication context) 
{ 
this.httpApp = context; 
//EventList.Clear(); 
EventList.Add("Initiated"); 
context.BeginRequest += new EventHandler(context_BeginRequest); 
context.AuthenticateRequest += new EventHandler(context_AuthenticateRequest); 
context.AuthorizeRequest += new EventHandler(context_AuthorizeRequest); 
context.ResolveRequestCache += new EventHandler(context_ResolveRequestCache); 
context.AcquireRequestState += new EventHandler(context_AcquireRequestState); 
context.PreRequestHandlerExecute += new EventHandler(context_PreRequestHandlerExecute); 
context.PostReleaseRequestState += new EventHandler(context_PostReleaseRequestState); 
context.ReleaseRequestState += new EventHandler(context_ReleaseRequestState); 
context.UpdateRequestCache += new EventHandler(context_UpdateRequestCache); 
context.EndRequest += new EventHandler(context_EndRequest); 
} 
private void context_EndRequest(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: End Request <hr>"); 
foreach (string str in EventList) 
{ 
httpApp.Response.Write(str + "<br>"); 
} 
EventList.Clear(); 
} 
void context_UpdateRequestCache(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Update Request Cache"); 
} 
void context_ReleaseRequestState(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Release Request State"); 
} 
void context_PostReleaseRequestState(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Post Release Request State"); 
} 
void context_PreRequestHandlerExecute(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Pre Request Handler Execution"); 
} 
void context_AcquireRequestState(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Acquire Request State"); 
} 
void context_ResolveRequestCache(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Resolve Request"); 
} 
void context_AuthorizeRequest(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Authorize Request"); 
} 
void context_AuthenticateRequest(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: AuthenticateRequest"); 
} 
void context_BeginRequest(object sender, EventArgs e) 
{ 
EventList.Add("HTTP Modules: Begin Request"); 
} 
}

4. 修改刚才的Default.aspx的后台cs代码：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
public partial class _Default : System.Web.UI.Page 
{ 
protected void Page_Init() 
{ 
TestClass.EventList.Add("ASP.NET Page: Page_Init"); 
} 
protected void Page_Load(object sender, EventArgs e) 
{ 
TestClass.EventList.Add("ASP.NET Page: Page_Load"); 
} 
public override void Validate() 
{ 
TestClass.EventList.Add("ASP.NET Page: Validated"); 
base.Validate(); 
} 
protected void btnSubmit_Click(object sender, EventArgs e) 
{ 
TestClass.EventList.Add("ASP.NET Page: Event"); 
} 
protected override void Render(HtmlTextWriter writer) 
{ 
TestClass.EventList.Add("ASP.NET Page: Render"); 
base.Render(writer); 
} 
protected void Page_Unload(object sender, EventArgs e) 
{ 
TestClass.EventList.Add("ASP.NET Page: Unload"); 
} 
}

5. 修改web.config内容如下：

<configuration> 
<system.web> 
<compilation debug="true" targetFramework="4.0"/> 
</system.web> 
<system.web> 
<httpModules> 
<add name="TestClass" type="TestClass"/> 
</httpModules> 
</system.web> 
</configuration>

6. Ctrl+F5执行，在浏览器里可以看到：



7. 在文本框内输入内容，可得：

　


结论：
1. Module只初始化了一次，当页面postback的时候，module不会再初始化。
2. Validate和Event事件在页面第一次初始化的时候不会触发，但是由于页面本身存在validate控件和事件按钮，所以这两个事件在第二次会被触发。
本文参考了codeproject.com的如下一篇文章http://www.codeproject.com/KB/aspnet/ASPDOTNETPageLifecycle.aspx