ASP.NET利用JavaScript实现无刷新闪烁二级联动菜单-优快云博客

本文介绍了一个基于ASP.NET的Web窗体应用程序如何实现下拉列表的联动功能，通过C#代码展示了如何从数据库获取大类和小类信息，并在用户选择大类时动态更新小类选项。

News_Aclass表---大类表
ClassID Int 4
ClassName varchar 50

News_Anclass表---小类表
NclassID int 4
Nclass varchar 50
ClassID int 4

---------------------------------aspx------------------------------

@ Page language="c#" Codebehind="test.aspx.cs" AutoEventWireup="false" Inherits="HoverPortal.Modules.NewsManager.test" enableViewState="False"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >

<HTML>

<HEAD>

</HEAD>

<body>

<asp:DropDownList id="ClassID" runat="server" onChange="changelocation(document.Form1.ClassID.options[document.Form1.ClassID.selectedIndex].value)"></asp:DropDownList>

<asp:DropDownList id="NclassID" runat="server"></asp:DropDownList>

<asp:Button id="Button1" runat="server" Text="Button"></asp:Button>

</form>

</body>

</HTML>

-----------------------------------cs------------------------------------------

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

using Microsoft.ApplicationBlocks.Data;

namespace HoverPortal.Modules.NewsManager

{

/**//// <summary>

/// test 的摘要说明。

/// </summary>

public class test : System.Web.UI.Page

{

protected System.Web.UI.WebControls.DropDownList NclassID;

protected System.Web.UI.WebControls.Button Button1;

protected System.Web.UI.WebControls.DropDownList ClassID;

private void Page_Load(object sender, System.EventArgs e)

{

// 在此处放置用户代码以初始化页面

ReWriteScript();

//if(!Page.IsPostBack )

DataBinds();

}

private void ReWriteScript()

{

int count=0;

string scriptString="<Script Language=JavaScript>\n var onecount;";

scriptString +="\nonecount=0;";

scriptString +="\nsubcat=new Array();";

SqlDataReader rs=this.GetNclass();

while(rs.Read())

{

scriptString +="\n subcat["+count+"]=new Array("+"'"+rs["Nclass"]+"'"+","+"'"+rs["classID"]+"'"+","+"'"+rs["NclassID"]+"'"+");";

count++;

}

rs.Close();

scriptString +="\n onecount="+count+";";

scriptString +="\n function changelocation(locationid){";

scriptString +="\n document.Form1.NclassID.length = 0;";

scriptString +="\n var locationid=locationid;";

scriptString +="\n var i;";

scriptString +="\n for(i=0; i<onecount; i++){";

scriptString +="\n if(subcat[i][1]==locationid){";

scriptString +="\n document.Form1.NclassID.options[document.Form1.NclassID.length]=new Option(subcat[i][0],subcat[i][2]);";

scriptString +="\n }";

scriptString +="<";

scriptString +="/";

scriptString +="script>";

if(!this.IsClientScriptBlockRegistered("clientScript"))

{

this.RegisterClientScriptBlock("clientScript",scriptString);

}

private SqlDataReader GetNclass()

{

SqlDataReader NclassReader=SqlHelper.ExecuteReader(SqlDbObject.Connection,CommandType.StoredProcedure,"sp_News_GetNClass");

return NclassReader;

}

private DataSet Getclass()

{

DataSet Classds=SqlHelper.ExecuteDataset(SqlDbObject.Connection,CommandType.StoredProcedure,"sp_News_GetClass");

return Classds;

}

private DataSet Getnclass()

{

DataSet Classds=SqlHelper.ExecuteDataset(SqlDbObject.Connection,CommandType.StoredProcedure,"sp_News_GetNClass");

return Classds;

}

private DataSet Getnclass(int classid)
  {
   SqlParameter[] parameter={new SqlParameter("@ClassID",SqlDbType.Int,4)};
   parameter[0].Value=classid;
   using(DataSet ds=SqlHelper.ExecuteDataset(SqlDbObject.Connection,CommandType.StoredProcedure,"Sp_News_GetNclassBYclassID",parameter))
   {
    return ds;
   }
  }

private void DataBinds()

{

DataTable dt=this.Getclass().Tables[0]; //获得大类列表

this.ClassID.DataSource=dt;

this.ClassID.DataTextField="ClassName";

this.ClassID.DataValueField="ClassID";

this.ClassID.DataBind();

DataTable dtn=Getnclass(int.Parse(this.ClassID.SelectedValue)).Tables[0]; //根据大类列表默认选中项读出所属的小类列表

this.NclassID.DataSource=dtn;

this.NclassID.DataTextField="Nclass";

this.NclassID.DataValueField="NclassID";

this.NclassID.DataBind();