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);
}
是client side的callback，最主要就是上面的getcallbackeventreference不懂，arg是干嘛的，在哪里可以应用或者引用对应的？同样context是在哪里引用？callbackscript的作用是啥呢？registerclientscriptblock在这里干嘛？每个参数啥意思？
下面是aspx的内容
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ClientCallbacks.aspx.cs" Inherits="ClientCallbacks" %>
<!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>未命名页面</title>
<script type="text/JavaScript">
function DoSearch()
{
var txtFirstName = document.getElementById("txtUserName");
CallServer(txtFirstName.value, "");
}
function ReceiveServerData(txtUserInfo)
{
Results.innerText = txtUserInfo;
}
setInterval('DoSearch()',1000);
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
姓名：<input id="txtUserName" type="text" /><br />
<span ID="Results" style="background-color: pink; width: 500px;"></span>
</div>
</form>
</body>
</html>
下面是对应的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 System.Data.SqlClient;
public partial class ClientCallbacks : System.Web.UI.Page,ICallbackEventHandler
{
protected string txtUserInfo;
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);
}
public void RaiseCallbackEvent(string txtFirstName)
{
if (txtFirstName != null)
{
SqlConnection conn = new SqlConnection("data source=.;initial catalog=Northwind;user id=sa1;password=sa1");
conn.Open();
SqlCommand cmd = new SqlCommand("select EmployeeID,FirstName,City,Address from Employees where FirstName=@FirstName", conn);
cmd.Parameters.Add("@FirstName", SqlDbType.NVarChar, 10).Value = txtFirstName;
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
txtUserInfo = "员工代号：" + dr["EmployeeID"] + " ,";
txtUserInfo += "姓名：" + dr["FirstName"] + " ,";
txtUserInfo += "居住城市：" + dr["City"] + " ,";
txtUserInfo += "地址：" + dr["Address"].ToString().Replace("\r\n","") + " ,";
txtUserInfo += "服务器查询时间：" + DateTime.Now.ToLongTimeString();
}
else
{
if (String.IsNullOrEmpty(txtFirstName))
{
txtUserInfo = "请输入姓名";
}
else
{
txtUserInfo = "查无此人！";
}
}
cmd.Dispose();
dr.Dispose();
conn.Dispose();
}
}
public string GetCallbackResult()
{
return txtUserInfo; }
}
maiyude
