我一直在做C#多年,但ASP.NET不那么久,这让我难住。为什么在Javascript中附加事件处理程序会阻止我的服务器端事件触发?
在我的故障诊断示例中,我在ASP.NET页面中有一个下拉列表,它有四个项目,我有一个在selectedindexchanged
上触发的serverside事件,它在这种情况下都很好。但是,如果(因为我在我的演变代码中)为“onchange”事件设置了Javascript处理程序(它启动警报),警报正常工作,但服务器端事件不再触发...我确定我错过了一些明显的东西。
重要提示:Autopostback
设置为true的下拉列表控制,视图状态已启用,JavaScript的事件处理程序返回true
有人吗?
这不是我必须手动连线__doPostBack
是吗?
任何帮助非常感谢。
编辑
确定这里是代码的第一代码隐藏
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
namespace TestEvents
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected override void OnPreRender(EventArgs e)
{
ClientScriptManager csm = Page.ClientScript;
if (!csm.IsClientScriptBlockRegistered("NotesChangeScript"))
{
StringBuilder sb = new StringBuilder();
sb.Append("\r\n <script type=\"text/javascript\"> \r\n");
sb.Append(" //<![CDATA[ \r\n");
sb.Append(" var changesCount = 0; \r\n");
sb.Append(" function selection_handler()\r\n");
sb.Append("{ \r\n");
sb.Append(" changesCount += 1;\r\n");
sb.Append(" alert('i changed on the client!'); \r\n");
sb.Append(" return true; \r\n");
sb.Append(" } \r\n");
sb.Append(" function SetUpNotesHandler() \r\n");
sb.Append("{ \r\n");
sb.Append(" var ctrls = document.getElementsByTagName(\"SELECT\");\r\n");
sb.Append(" for(i=0;i<ctrls.length;i++)\r\n");
sb.Append(" {\r\n");
sb.Append(" ctrls[i].onchange = selection_handler; \r\n");
sb.Append(" }\r\n");
sb.Append("}\r\n");
sb.Append(" //]]> \r\n");
sb.Append("</script>");
csm.RegisterClientScriptBlock(this.GetType(), "NotesChangeScript", sb.ToString(), false);
StringBuilder initScript = new StringBuilder();
initScript.Append("<script type=\"text/javascript\" >\r\n");
initScript.Append(" //<![CDATA[\r\n");
initScript.Append(" SetUpNotesHandler(); \r\n");
initScript.Append(" //]]> \r\n");
initScript.Append("</script> \r\n");
csm.RegisterStartupScript(this.GetType(), "StartUpKey", initScript.ToString(),false);
base.OnPreRender(e);
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write("i hit the server event");
}
}
}
这里是页面
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="TestEvents._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>problem</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem>Numero Uno</asp:ListItem>
<asp:ListItem>Numer Deux</asp:ListItem>
<asp:ListItem>Number Three</asp:ListItem>
<asp:ListItem>Nomina Quatros</asp:ListItem>
</asp:DropDownList>
<asp:HiddenField ID="hdnFieldChange" runat="server" />
</div>
</form>
</body>
</html>
你能解释为什么事情租在我的情况下工作? – Matt 2009-03-01 00:45:08