ASP.NET Postback的Web Page生命周期-编程开发-知优网

本文介绍ASP.NET Postback，就得说Web Page生命周期，但是Web Page生命周期却不是三言两语就能够说得清楚的，所以在这里单纯站的编程的角度，撇开Web Page生命周期浅谈Postback。

说道ASP.NET Postback，就得说Web Page生命周期，可是Web Page生命周期却不是片言只语就可以说得清楚的，所以在这里单纯站的编程的视点，放下Web Page生命周期浅谈Postback。

ASP.NET Postback的Web Page生命周期 Web Postback 第1张

咱们知道，无论是ASP.NET1.x,2.0，乃至是今后的版别，ASP.NET终究Render到Client端经过阅读器阅读的都是相同：一个单纯的HTML。Client经过Submit Form的方法将填入Form的数据提交给Server进行处理。咱们现在来看看ASP.NET Postback程序处理的进程。

首要咱们经过一个Sample来看ASP.NET怎么处理一个经过Click一个Button引起的Postback。下面是Web Page的HTML：

<%@PageLanguage="C#"AutoEventWireup="true"CodeFile="Default.
aspx.cs"Inherits="_Default"%>
<!DOCTYPEhtmlPUBLIC"-//W3C//DTDXHTML1.0Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<htmlxmlnshtmlxmlns="http://www.w3.org/1999/xhtml">
<headrunatheadrunat="server">
<title>TestPage</title>
</head>
<body>
<formidformid="form1"runat="server">
<div>
<asp:Labelrunatasp:Labelrunat="server"ID="LabelMessage"ForeColor="red"></asp:Label>
</div>
<div>
<asp:Buttonrunatasp:Buttonrunat="server"ID="Button1"Text="Button1"OnClick=
"Button1_Click"OnCommand="Button_Command"CommandArgument="Button1"/>
<asp:Buttonrunatasp:Buttonrunat="server"ID="Button2"Text="Button2"OnClick=
"Button2_Click"OnCommand="Button_Command"CommandArgument="Button2"UseSubmitBehavior="false"/>
<asp:Buttonrunatasp:Buttonrunat="server"ID="Button3"Text="Button3"OnClick=
"Button3_Click"OnCommand="Button_Command"CommandArgument="Button3"UseSubmitBehavior="false"/>
</div>
</form>
</body>
</html>

很简单，界说了3个Button，别离注册了他们的两个Event：Click和Command。3个Button的Command Event Hander是相同的：Button_Command，经过指定的CommandArgument来让Event Handler判别到底是哪个Button触发了Command Event。

下面是Code Behind：

usingSystem; 
usingSystem.Data; 
usingSystem.Configuration; 
usingSystem.Web; 
usingSystem.Web.Security; 
usingSystem.Web.UI; 
usingSystem.Web.UI.WebControls; 
usingSystem.Web.UI.WebControls.WebParts; 
usingSystem.Web.UI.HtmlControls; 
publicpartialclass_Default:System.Web.UI.Page 
{ 
protectedvoidPage_Load(objectsender,EventArgse) 
{ 
} 
protectedvoidButton1_Click(objectsender,EventArgse) 
{ 
stringstringmessage=string.Format("The{0}eventof{1}isfired","Click","Button1"); 
this.LabelMessage.Text=message; 
} 
protectedvoidButton2_Click(objectsender,EventArgse) 
{ 
stringstringmessage=string.Format("The{0}eventof{1}isfired","Click","Button2"); 
this.LabelMessage.Text=message; 
} 
protectedvoidButton3_Click(objectsender,EventArgse) 
{ 
stringstringmessage=string.Format("The{0}eventof{1}isfired","Click","Button3"); 
this.LabelMessage.Text=message; 
} 
protectedvoidButton_Command(objectsender,CommandEventArgse) 
{ 
stringstringmessage=string.Format("The{0}eventof{1}isfired",
"Command",e.CommandArgument); 
this.LabelMessage.Text+=";"+message; 
} 
}