Microsoft Asp.Net Ajax框架入门(10) ScriptManager, UpdatePanel, Timer

心已赠人 2022-01-06 05:55 163阅读 0赞

VS 2008  
  
本文介绍Microsoft Asp.Net Ajax框架的服务端重要控件  
  
**1. ScriptManager**  
ScriptManager控件被寓为Asp.Net Ajax的大脑，所有的Asp.Net Ajax Enabled Pages都必须包含有且仅有一个ScriptManager控件。

![None.gif][] < asp:ScriptManager ID = " scriptMgr " runat = " server " >  
![None.gif][] </ asp:ScriptManager >

包含了该控件，页面便会自动引用必需的Core Library脚本文件，并生成一些页面js。  
  
如要现在新建了一个User.js的脚本文件，并需要在页面中注册，则改为：

还可注册客户端js可调用的Web Services：

![None.gif][] < asp:ScriptManager ID = " scriptMgr " runat = " server " >  
![None.gif][] < Scripts >  
![None.gif][] < asp:ScriptReference Path = " ~/User.js " />  
![None.gif][] </ Scripts >  
![None.gif][] < Services >  
![None.gif][] < asp:ServiceReference Path = " ~/CountrySvc.asmx " />  
![None.gif][] </ Services >  
![None.gif][] </ asp:ScriptManager >

这样，ScriptManager会为Web Service生成一个客户端脚本的web service访问代理，供客户端调用。  
**2. ScriptMangerProxy**  
 一个页面只能有一个ScriptManager控件，但，如果页面使用MasterPage, ContentPage, 通常ScriptManager会置于MasterPage，在那里注册通用的js或web service，那么，在Content Page中可能也需要注册只需要当前页面调用的js或Web Service，那么就需要用到ScriptManagerProxy控件。  
ScriptManagerProxy继承自ScriptManager。

![None.gif][] < asp:ScriptManagerProxy ID = " sriptMgrPxy " runat = " server " >  
![None.gif][] < Scripts >  
![None.gif][] < asp:ScriptReference Path = " Company.js " />  
![None.gif][] </ Scripts >  
![None.gif][] < Services >  
![None.gif][] < asp:ServiceReference Path = " CompanySvc.asmx " />  
![None.gif][] </ Services >  
![None.gif][] </ asp:ScriptManagerProxy >

**3. UpdatePanel**  
 UpdatePanel定义了部分页面更新的区域，html写在ContentTemplate里面  
例：

![ExpandedBlockStart.gif][] protected void btnShowName\_Click( object sender, EventArgs e) \{  
![InBlock.gif][] txtName.Text = "guozhijian";  
![ExpandedBlockEnd.gif][] \}

点击btnShowName控件，txtName文本框的值改变了，页面没有回刷  
  
一个页面可以包含多个UpdatePanel：

![None.gif][] < asp:UpdatePanel ID = " uPanel1 " runat = " server " >  
![None.gif][] < ContentTemplate >  
![None.gif][] < asp:TextBox ID = " txtName " runat = " server " />  
![None.gif][] < asp:Button ID = " btnShowName " runat = " server " Text = " show name " OnClick = " btnShowName\_Click " />  
![None.gif][] </ ContentTemplate >  
![None.gif][] </ asp:UpdatePanel >  
![None.gif][] < asp:UpdatePanel ID = " uPanel2 " runat = " server " >  
![None.gif][] < ContentTemplate >  
![None.gif][] < asp:TextBox ID = " txtAge " runat = " server " />  
![None.gif][] < asp:Button ID = " btnShowAge " runat = " server " Text = " show age " OnClick = " btnShowAge\_Click " />  
![None.gif][] </ ContentTemplate >  
![None.gif][] </ asp:UpdatePanel >

![ExpandedBlockStart.gif][] protected void btnShowName\_Click( object sender, EventArgs e) \{  
![InBlock.gif][] txtName.Text = "guozhijian";  
![ExpandedBlockEnd.gif][] \}  
![ExpandedBlockStart.gif][] protected void btnShowAge\_Click( object sender, EventArgs e) \{  
![InBlock.gif][] txtAge.Text = "26";  
![ExpandedBlockEnd.gif][] \}

触发UpdatePanel更新的控件可以至于UpdatePanel外部，这是需要设置UpdatePanle的 UpdateMode="Conditional"，并设置UpdatePanel的<Triggers>：

![None.gif][] < asp:UpdatePanel ID = " uPanel1 " runat = " server " UpdateMode = " Conditional " >  
![None.gif][] < ContentTemplate >  
![None.gif][] < asp:TextBox ID = " txtName " runat = " server " />  
![None.gif][] </ ContentTemplate >  
![None.gif][] < Triggers >  
![None.gif][] < asp:AsyncPostBackTrigger ControlID = " btnShowName " />  
![None.gif][] </ Triggers >  
![None.gif][] </ asp:UpdatePanel >  
![None.gif][]  
![None.gif][] < asp:Button ID = " btnShowName " runat = " server " Text = " show name " OnClick = " btnShowName\_Click " />

如果一个页面包含多个UpdatePanel，默认情况下如果任何一个UpdatePanel被触发更新，那么都会触发所有UpdatePanel的更新，为避免这一情况发生，建议总是设置UpdatePanel的UpdateMode="Conditional“，指定各自的AsyncPostBackTrigger。  
  
**4. Timer**  
 Timer控件用于创建一个定时执行的任务，例：在一个TextBox控件中显示当前时间，每秒刷一次

![None.gif][] < asp:UpdatePanel ID = " uPanel1 " runat = " server " UpdateMode = " Conditional " >  
![None.gif][] < ContentTemplate >  
![None.gif][] < asp:TextBox ID = " txtTime " runat = " server " />  
![None.gif][] </ ContentTemplate >  
![None.gif][] < Triggers >  
![None.gif][] < asp:AsyncPostBackTrigger ControlID = " timer1 " />  
![None.gif][] </ Triggers >  
![None.gif][] </ asp:UpdatePanel >  
![None.gif][] < asp:Timer ID = " timer1 " OnTick = " timer1\_Tick " runat = " server " Interval = " 1000 " />

![ExpandedBlockStart.gif][] protected void timer1\_Tick( object sender, EventArgs e) \{  
![InBlock.gif][] txtTime.Text = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");  
![ExpandedBlockEnd.gif][] \}

**5. Exception Handler**  
如何异步回刷请求提交后，出现异常，那么在客户端会有一个alert提示框提示异常信息

![ExpandedBlockStart.gif][] protected void btnShowName\_Click( object sender, EventArgs e) \{  
![InBlock.gif][] throw new Exception("没有取到名字");  
![ExpandedBlockEnd.gif][] \}

如果，需要对页面的异步回刷请求做统一异常处理，那么可以订阅ScirptManager的AsyncPostBackError

![None.gif][] protected void Page\_Load( object sender, EventArgs e)  
![ExpandedBlockStart.gif][] \{  
![InBlock.gif][] ScriptManager mgr = ScriptManager.GetCurrent(this.Page);  
![InBlock.gif][] mgr.AsyncPostBackError += new EventHandler<AsyncPostBackErrorEventArgs>(mgr\_AsyncPostBackError);  
![ExpandedBlockEnd.gif][] \}  
![None.gif][]  
![ExpandedBlockStart.gif][] void mgr\_AsyncPostBackError( object sender, AsyncPostBackErrorEventArgs e) \{  
![InBlock.gif][] //  
![InBlock.gif][] ScriptManager.GetCurrent(this.Page).AsyncPostBackErrorMessage = "we are sorry";  
![ExpandedBlockEnd.gif][] \}

当ScriptManager的AsyncPostBackError事件触发时，设置 AsyncPostBackErrorMessage

Reference from : [http://www.cnblogs.com/guozhijian/archive/2008/02/17/1071242.html][http_www.cnblogs.com_guozhijian_archive_2008_02_17_1071242.html]

转载于:https://www.cnblogs.com/zhangchenliang/archive/2013/03/21/2973218.html

[None.gif]: /images/20211227/993f251771f24cc08bdb81863eb5d842.png
[ExpandedBlockStart.gif]: /images/20211227/2e27d50bde544013a668dbe9c4c1c310.png
[InBlock.gif]: /images/20211227/eb60e76f8fc940ceb5a977408bfa41ea.png
[ExpandedBlockEnd.gif]: /images/20211227/d54ca01dd20849ae96140b5b40282b31.png
[http_www.cnblogs.com_guozhijian_archive_2008_02_17_1071242.html]: http://www.cnblogs.com/guozhijian/archive/2008/02/17/1071242.html