This is using ajax technology, the refresh is certain, and it is completed at a speed that we are not aware of. The XMLHTTP sacrifice page method, the reason why we cannot see the refresh is because all the work is performed on the sacrifice page, inside " We can't see the "tossing" of the world, and the efficiency is worse!
AjaxPro.dll download address <configuration>
<system.web>
<httpHandlers>
<add verb="POST,GET" path="ajax/*.ashx" type="Ajax.PageHandlerFactory, Ajax" />
<add verb="POST,GET" path="ajaxpro/*.ashx" type="AjaxPro.AjaxHandlerFactory,AjaxPro.2"/>
</httpHandlers>
</system.web>
</configuration>
AjaxTest.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="AjaxTest.aspx.cs" Inherits="AjaxTest" %>
<!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>Untitled page</title>
</head>
<body>
<script language="javascript" type="text/javascript">
function areaResult()
{
var area=document.getElementById("DropDownList1");
//alert(area.value);
AjaxTest.GetCityList(area.value,get_city_Result_CallBack);
}
function get_city_Result_CallBack(response)
{
if (response.value != null)
{
document.all("DropDownList2").length=0;
var ds = response.value;
if(ds != null && typeof(ds) == "object" && ds.Tables != null)
{
for(var i=0; i<ds.Tables[0].Rows.length; i++)
{
var name=ds.Tables[0].Rows[i].name;
var id=ds.Tables[0].Rows[i].id;
document.all("DropDownList2").options.add(new Option(name,id));
}
//document.all("TextBox1").value="";
}
}
return
}
</script>
<form id="form1" runat="server">
<asp:DropDownList ID="DropDownList1" runat="server">
</asp:DropDownList>
<asp:DropDownList ID="DropDownList2" runat="server">
</asp:DropDownList>
<br />
</form>
</body>
</html>
AjaxTest.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 MeetWeb;
public partial class AjaxTest : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
AjaxPro.Utility.RegisterTypeForAjax(typeof(AjaxTest));
if (!Page.IsPostBack)
{
BindData();
}
}
private void BindData()
{
DataSet ds = new DataSet();
String sql = "Select id,name from test";
try
{
ds = GetDataSet(sql, "test");
this.DropDownList1.DataSource = ds.Tables[0];
this.DropDownList1.DataTextField = "name";
this.DropDownList1.DataValueField = "id";
this.DropDownList1.DataBind();
this.DropDownList1.Attributes.Add("onclick", "areaResult();");
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
}
public static DataSet GetDataSet(string sql, string aa)
{
MeetWeb.SqlDataBase a = new MeetWeb.SqlDataBase("server=localhost\PMSERVER;uid=sa;pwd=sa;database=test");
DataSet ds = new DataSet();
ds=a.CreateSet(sql, aa);
return ds;
}
[AjaxPro.AjaxMethod]
public DataSet GetCityList(int id)
{
string sql = "select name from test where id='" + id + "'";
return GetDataSet(sql,"test");
}
}