异步回调方法的使用
来自MSDN：
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Text;
public partial class newSource_callback : System.Web.UI.Page,ICallbackEventHandler
{
public int cbCount = 0;
//public string cbcount = "";
public void RaiseCallbackEvent(String eventArgument)
{
cbCount = Convert.ToInt32(eventArgument) + 1;
//cbcount = eventArgument;
}
public string GetCallbackResult()
{
return cbCount.ToString();
//return cbcount;
}
protected void Page_Load(object sender, EventArgs e)
{
StringBuilder sb = new StringBuilder();
sb.Append("No page postbacks have occurred.");
if (Page.IsPostBack)
{
sb.Append("A page postback has occurred.");
}
MyLabel.Text = sb.ToString();
ClientScriptManager cs = Page.ClientScript;
StringBuilder context1 = new StringBuilder();
context1.Append("function ReceiveServerData1(arg, context){Message1.innerText = arg;value1 = arg;}");
//context1.Append("{");
//context1.Append("Message1.innerText = arg;");
//context1.Append("value1 = arg;");
//context1.Append("}");
String cbReference1 = cs.GetCallbackEventReference(this, "arg",
"ReceiveServerData1", context1.ToString());
String cbReference2 = cs.GetCallbackEventReference("'" +
Page.UniqueID + "'", "arg", "ReceiveServerData2", "",
"ProcessCallBackError", false);
String callbackScript1 = "function CallTheServer1(arg, context) {" +
cbReference1 + "; }";
String callbackScript2 = "function CallTheServer2(arg, context) {" +
cbReference2 + "; }";
cs.RegisterClientScriptBlock(this.GetType(), "CallTheServer",
callbackScript1, true);
cs.RegisterClientScriptBlock(this.GetType(), "CallTheServer2",
callbackScript2, true);
}
}
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="callback.aspx.cs" Inherits="newSource_callback" %>
<!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>无标题页</title>
<script type="text/javascript">
var value1 = 0;
var value2 = 0;
function ReceiveServerData2(arg, context)
{
Message2.innerText = arg;
value2 = arg;
}
function ProcessCallBackError(arg, context)
{
Message2.innerText = 'An error has occurred.';
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
Callback 1 result: <span id="Message1">0</span>
<br />
Callback 2 result: <span id="Message2">0</span>
<br /> <br />
<input type="button"
value="ClientCallBack1"
onclick="CallTheServer1(value1, alert('Increment value'))"/>
<input type="button"
value="ClientCallBack2"
onclick="CallTheServer2(value2, alert('Increment value'))"/>
<br /> <br />
<asp:Label id="MyLabel"
runat="server"></asp:Label>
</div>
</form>
</body>
</html>
