ASP.NET 生命周期

ASP.NET 生命周期
对于Asp.net页面层开发无论是写页面还是写控件，我觉得都可以用一句话描述:"Do the right thing at the right time in the right place."
本文通过记录页面事件的触发顺序看请求的处理流程，从中可以看出ASP.NET 的生命周期

创建一个网站，在页面上添加一个Label和一个Button，在Default.aspx.cs中修改代码如下：

 

using System;using System.Configuration;using System.Data;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;public partial class _Default : System.Web.UI.Page { protected void Page_PreInit(object sender, EventArgs e) { Response.Write("Page_PreInit<br/>"); } protected void Page_Init(object sender, EventArgs e) { Response.Write("Page_Init<br/>"); } protected void Page_InitComplete(object sender, EventArgs e) { Response.Write("Page_InitComplete<br/>"); } protected void Page_PreLoad(object sender, EventArgs e) { Response.Write("Page_PreLoad<br/>"); } protected void Page_Load(object sender, EventArgs e) { Response.Write("Page_Load<br/>"); } protected void Page_LoadComplete(object sender, EventArgs e) { Response.Write("Page_LoadComplete<br/>"); } protected void Page_PreRender(object sender, EventArgs e) { Response.Write("Page_PreRender<br/>"); } protected void Page_PreRenderComplete(object sender, EventArgs e) { Response.Write("Page_PreRenderComplete<br/>"); } protected void Page_SaveStateComplete(object sender, EventArgs e) { Response.Write("Page_SaveStateComplete<br/>"); } protected void Page_Unload(object sender, EventArgs e) { int i = 0; i++; ////这行代码是用来设置断点的 } //protected void Button1_Click(object sender, EventArgs e) //{ // Label1.Text = "ControlEvent"; // Response.Write("Button事件触发!<br/>"); //} protected void Button1_Click1(object sender, EventArgs e) { Label1.Text = "ControlEvent"; Response.Write("Button事件触发!<br/>"); }}

 

运行结果：
Page_PreInit
Page_Init
Page_InitComplete
Page_PreLoad
Page_Load
Page_LoadComplete
Page_PreRender
Page_PreRenderComplete
Page_SaveStateComplete

点击Button按钮后结果为：
Page_PreInit
Page_Init
Page_InitComplete
Page_PreLoad
Page_Load
Button事件触发!
Page_LoadComplete
Page_PreRender
Page_PreRenderComplete
Page_SaveStateComplete

从以上事例，我们就可以清楚看出页面的生命周期。
为什么要在Page_Unload事件中添加断点，从Page_Unload事件的功能中就可以发现缘由。
Page_Unload：完成页面呈现之后，将激发 Page_Unload 事件。此事件是执行最终清理工作的合适位置。这包括清理打开的数据库连接、丢弃对象或关闭打开的文件等操作。