In addition to adding controlid to the triggers of updatepanel, The updatepanel refresh function also provides the method Update () function used in the previous article. I learned another method in this blog, we use _ dopostback () (two underscores) in JavaScript to achieve the page effect. When we click button1, the label in updatepanel1 gets the system time.
Note: the front-end function _ dopostback is mainly used for the Web Control PostBack. It sends control information to the server through the two hidden controls _ eventtraget ,__ eventargument.
Page Layout: 1. Drag and Drop scriptmanager1.
2. Put updatepanel1 and set updatemode = conditional of updatepanel1.
3. In updatepanel1, add label1.
4. Put an HTML button1.
PageSource codeAs follows: When you click button1, the _ dopostback function is triggered, causing the page to refresh.
Note _ dopostback usage
1 <% @ Page Language = " C # " Autoeventwireup = " True " Codefile = " Default. aspx. CS " Inherits = " _ Default " %>
2 <! Doctype HTML public " -// W3C // dtd xhtml 1.0 transitional // en " " Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >
3 < HTML xmlns = " Http://www.w3.org/1999/xhtml " >
4 < Head runat = " Server " >
5 < Title > No title page </ Title >
6 </ Head >
7 < Body >
8 < Form ID = " Form1 " Runat = " Server " >
9 < Div >
10 < ASP: scriptmanager ID = " Scriptmanager1 " Runat = " Server " >
11
12 </ ASP: scriptmanager >
13 < Script Language = " Javascript " >
14 Function comfirmrefresh ()
15 {
16 If (Confirm ( " Are you sure you want to refresh? " ))
17 {< br> 18 // the first parameter is the ID of the control you want to submit to the server, the second parameter is the event parameter
19 _ dopostback ( " updatepanel1 " , " refresh " );
20 }
21 }
22 </ Script >
23 < Input ID = " Button1 " Type = " Button " Value = " Button " Onclick = " Comfirmrefresh () " />
24 < ASP: updatepanel ID = " Updatepanel1 " Runat = " Server " Updatemode = " Conditional " >
25 < Contenttemplate >
26 < ASP: Label ID = " Label1 " Runat = " Server " Text = " Label " > </ ASP: Label >
27 </ Contenttemplate >
28 </ ASP: updatepanel >
29 </ Div >
30 </ Form >
31 </ Body >
32 </ Html >
33
CSCodeAs follows:
Page loading is used to determine whether the page is partially refreshed
1 Public Partial Class _ Default: system. Web. UI. Page
2 {
3 Protected Void Page_load ( Object Sender, eventargs E)
4 { // When the current value of scriptmanager1 sending back is asyncpostback and the control that causes the asynchronous sending back event of scriptmanager1 is updatepanel1.
5 If (Scriptmanager1.isinasyncpostback && Scriptmanager1.asyncpostbacksourceelementid = " Updatepanel1 " )
6 // Label1 obtains the current system time.
7 Label1.text = Datetime. Now. tostring ();
8 }
9 }
10
