ASP.NET回调 [英] ASP.NET callback
问题描述
我已经编写了一个示例ASP.NET(2.0)表单来演示回调脚本.回调链接到下拉列表的OnChange事件. I have written a sample ASP.NET ( 2.0) form to demo callback scripting. The callback is linked to the OnChange event of a dropdownlist. 受保护的 Page_Load( 发件人 e)
{ protected void Page_Load(object sender, EventArgs e)
{ 如果 (Page.IsCallback)
{ if (Page.IsCallback)
{ tb2.Text = tb2.Text = "CB" ;
} "CB";
} 如果 (Page.IsPostBack)
{ if (Page.IsPostBack)
{ tb2.Text = tb2.Text = "PB" ;
} "PB";
} 如果 (!Page.IsPostBack)
{ if (!Page.IsPostBack)
{ tb2.Text = tb2.Text = "" ; "";
字符串callbackeventreference = Page.ClientScript.GetCallbackEventReference(this,"document.all ['ddl1'].value","CallbackFunction" ;,"null"); ddl1.Attributes [ ddl1.Attributes[ "onChange" ] = callbackeventreference; } "onChange"] = callbackeventreference; } 首页 › 这篇关于ASP.NET回调的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
问题是,回调仅在我第一次更改下拉列表时触发.对于下拉列表中会话中的所有其他onchange事件,不会触发回调.我究竟做错了什么 ?这与Javascript脚本函数在ASP html页面中的放置有关吗?
另一个令人困惑的事情是,在我的页面加载中,我检查是否正在发生Page.IsPostback或Page.IsCallBack .但是调试这表明代码在执行onChange时会同时通过Page.IsCallback和Page.IsPostback传递!我相信它们是互斥的(例如,如果发生回调,那么回发就不能,反之亦然).
作为ASP.NET的新成员,我需要您对此领域的见识.
我的页面实现了 ICallbackEventHandler ,它具有 RaiseCallbackEvent& GetCallbackResult函数,这就是我如何将它们全部整合到PageLoad
stat = " ;
Problem is that the callback fires only the first time I do a change to the dropdownlist. For all other onchange events in the session on the dropdownlist, the callback does not fire. What am I doing wrong ? Has this got to do with the placement of the Javascript script function in the ASP html page ?
Another confusing thing is that on my Page load I check whether a Page.IsPostback or Page.IsCallBack is taking place. But debugging this indicates that the code passes thru both Page.IsCallback and Page.IsPostback while doing the onChange !! I believed that these were mutually exclusive ( i.e if a callback is happening then a postback cannot and vice versa) .
As a new ASP.NET entrant, I need your insights into this area.
My Page implements the ICallbackEventHandler , it has RaiseCallbackEvent & GetCallbackResult functions and this is how I put it all together in the PageLoad
static string stat = "";
}
}
非常感谢.
Thanks plenty.推荐答案