客户端回调实例
aspx：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ClientCallback.aspx.cs" Inherits="ClientCallback" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head id="Head1" runat="server">
<title>Client Callback Example</title>
<script type="text/ecmascript">
function LookUpStock()
{
var lb = document.getElementById("ListBox1");
var product = lb.options[lb.selectedIndex].text;
CallServer(product, "");
}
function ReceiveServerData(rValue)
{
document.getElementById("ResultsSpan").innerHTML = rValue;
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ListBox ID="ListBox1" Runat="server"></asp:ListBox>
<br />
<br />
<button type="Button" onclick="LookUpStock()">Look Up Stock</button>
<br />
<br />
Items in stock: <span id="ResultsSpan" runat="server"></span>
<br />
</div>
</form>
</body>
</html>
CS：
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 PowerTTS.DAL;
public partial class ClientCallback : System.Web.UI.Page, System.Web.UI.ICallbackEventHandler
{
protected System.Collections.Specialized.ListDictionary catalog;
protected String returnValue;
protected void Page_Load(object sender, EventArgs e)
{
String cbReference =
Page.ClientScript.GetCallbackEventReference(this,
"arg", "ReceiveServerData", "context");
String callbackScript;
callbackScript = "function CallServer(arg, context)" +
"{ " + cbReference + ";}";
Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
"CallServer", callbackScript, true);
catalog = new System.Collections.Specialized.ListDictionary();
catalog.Add("monitor", 12);
catalog.Add("laptop", 10);
catalog.Add("keyboard", 23);
catalog.Add("mouse", 17);
ListBox1.DataSource = catalog;
ListBox1.DataTextField = "key";
ListBox1.DataBind();
}
public void RaiseCallbackEvent(String eventArgument)
{
if (catalog[eventArgument] == null)
{
returnValue = "-1";
}
else
{
returnValue = catalog[eventArgument].ToString();
}
}
public String GetCallbackResult()
{
return returnValue;
}
}
