UpdatePanel的使用方法

UpdateMode：表示UpdatePanel的更新模式，有两个选项：Always和Conditional。Always是不管有没有Trigger，其他控件都将更新该UpdatePanel，Conditional表示只有当前UpdatePanel的Trigger，或ChildrenAsTriggers属性为true时当前UpdatePanel中控件引发的异步回送或者整页回送，或是服务器端调用Update()方法才会引发更新该UpdatePanel。
Contente Template：用来定义UpdatePanel的内容
Triggers：分别为AsyncPostBackTrigger和PostBackTrigger
AsyncPostBackTrigge用来指定某个服务器端控件以及其将触发的服务器端事件作为该UpdatePanel的异步更新触发器，它需要设置的属性有控件ID和服务端控件的事件；PostBackTrigger用来指定在UpdatePanel中的某个服务端控件，它所引发的回送不使用异步回送，而仍然是传统的整页回送
现在我们来做一个简单的实例：

<% @?Page?Language = " C# " ?AutoEventWireup = " true " ?CodeFile = " Default.aspx.cs " ?Inherits = " _Default "? %>

<! DOCTYPE?html?PUBLIC? " -//W3C//DTD?XHTML?1.1//EN "? " http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd " >

< html?xmlns = " http://www.w3.org/1999/xhtml " >

< head?runat = " server " >

???? < title > Untitled?Page </ title >

???? < style?type = " text/css " >

?????????body?

{?background-attachment:fixed;

?????????????

??????????????

????????????????background-image:url(Blue?hills.jpg);

????????????????}

????????????????

?????????.style1

?????????

{

????????????????background-position:top?center;

?????????}

?????????

?????????

???? </ style >

</ head >

< body??onload = " oSpan.className='style1' "? >

???? < form?id = " form1 " ?runat = " server " >

???? < span?style = " font-size:14;?width:250; " ?ID = " oSpan "

????????onmouSEOver = " this.className='style2' " ?onmouSEOut = " this.className='style1' " ></ span >

???????? < div >

???????????? < asp:ScriptManager?ID = " ScriptManager1 " ?????runat = " server " > ????

?????????????? </ asp:ScriptManager >

???????? </ div >

???????????

???????? < asp:UpdatePanel?ID = " uid " ??runat = " server " >

????????

???????????? < ContentTemplate >

????????????

???????????????? < div? >

???????????????????? < asp:Button?ID = " Button1 " ?runat = " server " ?Text = " 异步回送 " ?OnClick = " Button1_Click1 "? />& nbsp; & nbsp;

???????????????????? < asp:Button?ID = " Button2 " ?runat = " server " ?Text = " 整页回送 " ?OnClick = " Button2_Click "? />< br? />

???????????????????? < asp:GridView?ID = " GridView1 " ?runat = " server " ?AutoGenerateColumns = " False " ?Width = " 197px " >

???????????????????????? < Columns >

???????????????????????????? < asp:BoundField?DataField = " au_lname " ?FooterText = " aaaa " ?HeaderText = " au_lname "? />

???????????????????????? </ Columns >

???????????????????? </ asp:GridView >

???????????????????? < br? />

??????????????????? < asp:Label?ID = " Label1 " ?runat = " server " ?Text = " 当前时间 " ?Font - Bold = " True " ?Font - Size = " Large " ></ asp:Label >

?????????????????? </ div >

???????????? </ ContentTemplate >

???????????? < Triggers >

???????????????? < asp:AsyncPostBackTrigger????ControlID = " Button1 "? />

???????????????? < asp:PostBackTrigger??ControlID = " Button2 "? />

???????????? </ Triggers >

??????????????

???????? </ asp:UpdatePanel >

?????????? < div?id = " div1 "? >

?????????????? & nbsp; </ div >

????????

????????

???? </ form >

</ body >

</ html >