您的位置：首页 > 其它

ICallbackHandler实现GridView无刷新实时更新

2009-12-23 17:11 253 查看

GridView的数据显示一般是固定的,假如要像Ajax那样实现GridView数据动态更新而不刷新页面,就有些难度了.客户提出的需求,没办法,也得去试着想办法实现.

涉及到Asp.Net事件机制的实现"_doPostback".Asp.Net的底层封装了XMLHttpRequest异步请求对象.在WebResource.axd中可以查看到这些封装的JavaScript.对于页面的异步请求,我们需要实现ICallbackEventHandler接口,并显示实现其中的GetCallbackResult()和RaiseCallbackEvent()这两个方法.废话不多少,假如了解Asp.Net机制的话一看就明白了.代码就贴在下面:

后台代码：

using System;

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.IO;

using System.Globalization;

using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page, System.Web.UI.ICallbackEventHandler

{

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

Bind();

}

string cbReference = Page.ClientScript.GetCallbackEventReference(Page, "", "Refresh", "");

btnGet.Attributes.Add("onclick", cbReference);

string script = "";

script += "<script>/r/n";

script += "function Refresh(DataFromServer){/r/n";

script += "document.getElementById('Result').innerHTML=DataFromServer;/r/n";

script += "}/r/n</script>/r/n";

Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "Refresh", script);

}

public string GetCallbackResult()

{

//return RenderControl(Test);

return RenderControl(Test);

}

public void RaiseCallbackEvent(string eventArgument)

{

Bind();

}

private string RenderControl(Control c)

{

StringWriter writer1 = new StringWriter(CultureInfo.InvariantCulture);

HtmlTextWriter writer = new HtmlTextWriter(writer1);

c.RenderControl(writer);

writer.Flush();

writer.Close();

return writer1.ToString();

}

#region 数据绑定

public void Bind()

{

// 获取链接

SqlConnection conn = new SqlConnection();

// 设置连接的数据库

string str = "server=localhost;database=northwind;Integrated Security=True";

conn.ConnectionString = str;

// sql语句

string strSql = "SELECT EMPLOYEES.EMPLOYEEID, EMPLOYEES.FIRSTNAME, EMPLOYEES.LASTNAME, EMPLOYEES.TITLE FROM EMPLOYEES";

// 获取SqlDataAdapter对象

SqlDataAdapter adapter = new SqlDataAdapter(strSql, conn);

// 声明DataSet对象

DataSet ds = new DataSet();

// 填充DataSet

adapter.Fill(ds);

// 数据绑定

Test.DataSource = ds;

Test.DataBind();

}

#endregion

}

前台：

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_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>无标题页</title>

</head>

<body>

<form id="form1" runat="server">

<input type="button" runat="server" id="btnGet" value="Get" style="display:none"/>

<div id="Result">

<asp:GridView ID="Test" runat="server" CellPadding="4" ForeColor="#333333">

</asp:GridView>

</div>

</form>

<script type="text/javascript">function btnclick(){document.getElementById("btnGet").click();}setInterval("btnclick()",10000);</script>

</body>

</html>

程序中用到的数据库是Sql Server的示例数据库：northwind。

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航