驗證一個ASP.NET應用程序和頁面的生命周期的實現代碼

如果我們能更好地掌握這樣一個過程，那么對單個ASP.NET Page的生命周期也能更好地了解：
下面介紹如何編寫一個簡單的ASP.NET 頁面和一個簡單的HttpModule，對MSDN里提到的ASP.NET的生命周期進行驗證
1. 首先使用Visual Studio 2010建立一個空的ASP.NET網站 （ASP.NET 4.0）
2. 添加一個Default.aspx，添加三個ASP.NET控件，分別為TextBox，Button和Validator：
代碼如下:　　
<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. 添加一個ASP.NEt的App_code文件夾，新建一個類，內容為：
代碼如下:

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. 修改剛才的Default.aspx的后臺cs代碼： 
 代碼如下:

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內容如下： 
 代碼如下:

<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執行，在瀏覽器里可以看到：
 
7. 在文本框內輸入內容，可得：
　
結論： 
1. Module只初始化了一次，當頁面postback的時候，module不會再初始化。 
2. Validate和Event事件在頁面第一次初始化的時候不會觸發，但是由于頁面本身存在validate控件和事件按鈕，所以這兩個事件在第二次會被觸發。 
本文參考了codeproject.com的如下一篇文章http://www.codeproject.com/KB/aspnet/ASPDOTNETPageLifecycle.aspx 
 
 




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