XmlHttp实现无刷新三联动ListBox

本文介绍了一种使用XmlHttp实现的无刷新三级联动ListBox控件的技术方案。通过客户端JavaScript与服务器端C#的配合,实现了在不刷新页面的情况下动态加载下拉列表的内容。该方案适用于需要展示分层数据的Web应用。
1.html

<HTML>
<HEAD>
<title>XmlHttp实现无刷新三联动ListBox</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
<SCRIPT LANGUAGE="JavaScript">
<!--
//以XML求取ListBox2的数据
function XmlPost2(obj)
{
   var svalue = obj.value;
   var webFileUrl = "?povinceid=" + svalue;
   var result = "";
   var xmlHttp = new ActiveXObject("MSXML2.XMLHTTP");
   xmlHttp.open("POST", webFileUrl, false);
   xmlHttp.send("");
   result = xmlHttp.responseText;
  
   if(result != "")
   {
     document.all("ListBox2").length=0;
     var piArray = result.split(",");
     for(var i=0;i<piArray.length;i++)
     {
       var ary1 = piArray[i].toString().split("|");
       document.all("ListBox2").options.add(new Option(ary1[1].toString(),ary1[0].toString()));
     }
   }
   else
   {
     alert(result);
   }
}
//以XML求取ListBox3的数据
function XmlPost3(obj)
{
   var svalue = obj.value;
   var webFileUrl = "?cityid=" + svalue;
   var result = "";
   var xmlHttp = new ActiveXObject("MSXML2.XMLHTTP");
   xmlHttp.open("POST", webFileUrl, false);
   xmlHttp.send("");
   result = xmlHttp.responseText;
  
   if(result != "")
   {
     document.all("ListBox3").length=0;
     var piArray = result.split(",");
     for(var i=0;i<piArray.length;i++)
     {
       var ary1 = piArray[i].toString().split("|");
       document.all("ListBox3").options.add(new Option(ary1[1].toString(),ary1[0].toString()));
     }
   }
   else
   {
     alert(result);
   }
}
//-->
</SCRIPT>
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:ListBox id="ListBox1" style="Z-INDEX: 101; LEFT: 24px; POSITION: absolute; TOP: 16px" runat="server"
Height="448px" Width="200px"></asp:ListBox>
<asp:ListBox id="ListBox2" style="Z-INDEX: 102; LEFT: 352px; POSITION: absolute; TOP: 24px" runat="server"
Height="432px" Width="168px"></asp:ListBox>
<asp:ListBox id="ListBox3" style="Z-INDEX: 103; LEFT: 568px; POSITION: absolute; TOP: 24px" runat="server"
Height="424px" Width="200px"></asp:ListBox>
</form>
</body>
</HTML>


2.cs代码

public class WebForm2 : System.Web.UI.Page
{
protected System.Web.UI.WebControls.ListBox ListBox1;
protected System.Web.UI.WebControls.ListBox ListBox2;
protected System.Web.UI.WebControls.ListBox ListBox3;

public static string ConnectionString=System.Configuration .ConfigurationSettings .AppSettings["ConnectionString"];

GetDataSet#region GetDataSet
public static DataSet GetDataSet(string sql)
{
SqlDataAdapter sda =new SqlDataAdapter(sql,ConnectionString);
DataSet ds=new DataSet();
sda.Fill(ds);
return ds;
}
#endregion

property#region property
private string povinceid
{
get
{
if(ViewState["povinceid"]!=null && ViewState["povinceid"].ToString()!="")
{
return ViewState["povinceid"].ToString();
}
else
{
if(Request["povinceid"]!=null && Request["povinceid"].ToString()!="")
{
return Request["povinceid"];
}
else
{
return "";
}
}
}
set
{
ViewState["povinceid"]=value;
}
}
private string cityid
{
get
{
if(ViewState["cityid"]!=null && ViewState["cityid"].ToString()!="")
{
return ViewState["cityid"].ToString();
}
else
{
if(Request["cityid"]!=null && Request["cityid"].ToString()!="")
{
return Request["cityid"];
}
else
{
return "";
}
}
}
set
{
ViewState["povinceid"]=value;
}
}
#endregion

Page_Load#region Page_Load
private void Page_Load(object sender, System.EventArgs e)
{
if(!this.IsPostBack)
   {
     this.down1_bind();
this.ListBox1.Attributes.Add("onchange","XmlPost2(this);");
this.ListBox2.Attributes.Add("onchange","XmlPost3(this);");
   }
   if(povinceid != "")
   {
     this.down2_bind(povinceid);
   }
if(cityid != "")
   {
     this.down3_bind(cityid);
   }
}

#endregion

down2_bind#region down2_bind
private void down2_bind(string id)
{
   string mystr = "";
   string sql = "select cityID,city from city where father = '" + id + "'";
   DataSet ds = GetDataSet(sql);

   if(ds.Tables[0].Rows.Count != 0)
   {
     for(int i=0;i<ds.Tables[0].Rows.Count;i++)
     {
       mystr += "," + ds.Tables[0].Rows[i][0].ToString() + "|" + ds.Tables[0].Rows[i][1].ToString();
     }
     mystr = mystr.Substring(1);
   }
   this.Response.Write(mystr);
   this.Response.End();
}
#endregion

down3_bind#region down3_bind
private void down3_bind(string id)
{
   string mystr = "";
   string sql = "select areaID,area from area where father = '" + id + "'";
   DataSet ds = GetDataSet(sql);

   if(ds.Tables[0].Rows.Count != 0)
   {
     for(int i=0;i<ds.Tables[0].Rows.Count;i++)
     {
       mystr += "," + ds.Tables[0].Rows[i][0].ToString() + "|" + ds.Tables[0].Rows[i][1].ToString();
     }
     mystr = mystr.Substring(1);
   }
   this.Response.Write(mystr);
   this.Response.End();
}

#endregion

down1_bind#region down1_bind
private void down1_bind()
{
   string sql = "select provinceID,province from povince";
   DataSet ds = GetDataSet(sql);
   this.ListBox1.DataSource = ds;
   this.ListBox1.DataValueField = "provinceID";
   this.ListBox1.DataTextField = "province";
   this.ListBox1.DataBind();  
}

#endregion

Web Form Designer generated code#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}

/**//// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion
}

3.数据库下载http://dl.iteye.com/topics/download/c829bf89-42cf-355d-95bb-a4af8a0f8ee5
4.数据库脚本(3,4随便一个就可以)

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[area]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[area]
GO

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[city]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[city]
GO

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[povince]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[povince]
GO

CREATE TABLE [dbo].[area] (
[id] [int] NOT NULL ,
[areaID] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[area] [nvarchar] (60) COLLATE Chinese_PRC_CI_AS NULL ,
[father] [nvarchar] (6) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[city] (
[id] [int] NOT NULL ,
[cityID] [nvarchar] (6) COLLATE Chinese_PRC_CI_AS NULL ,
[city] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[father] [nvarchar] (6) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[povince] (
[id] [int] NOT NULL ,
[provinceID] [nvarchar] (6) COLLATE Chinese_PRC_CI_AS NULL ,
[province] [nvarchar] (40) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO
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