UpdateMode： 表示UpdatePanel的更新模式，有兩個選項：Always和Conditional。Always是無論有沒有Trigger，其它控件都將更新該UpdatePanel，Conditional表示僅僅有當前UpdatePanel的Trigger，或ChildrenAsTriggers屬性為true時當前UpdatePanel中控件引發的異步回送或者整頁回送，或是server端調用Update()方法才會引發更新該UpdatePanel。
Contente Template：用來定義UpdatePanel的內容
Triggers：分別為AsyncPostBackTrigger和PostBackTrigger
AsyncPostBackTrigge用來指定某個server端控件以及其將觸發的server端事件作為該UpdatePanel的異步更新觸發器，它須要設置的屬性有控件ID和服務端控件的事件；PostBackTrigger用來指定在UpdatePanel中的某個服務端控件，它所引發的回送不使用異步回送，而仍然是傳統的整頁回送
如今我們來做一個簡單的實例：

<% @?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 = " 異步回送 " ?OnClick = " Button1_Click1 " ? />& nbsp; & nbsp;
???????????????????? < asp:Button?ID = " Button2 " ?runat = " server " ?Text = " 整頁回送 " ?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 = " 當前時間 " ?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 >