UpdatePanel的用法

UpdateMode：表示UpdatePanel的更新模式，有两个选项：Always和Conditional。Always是无论有没有Trigger，其它控件都将更新该UpdatePanel，Conditional表示仅仅有当前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server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server端控件以及其将触发的server端事件作为该UpdatePanel的异步更新触发器，它须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
如今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
>