点击下拉框另一下拉框出现相应的内容

比方说表中
     building              foor
       1                    1
       1                    2
       1                    3
       1                    4
       2                    1
       2                    2
       2                    6
在一个下拉框显示
    1
    2
点击到1时,另一下拉框要出来   1
                          2
                          3
                          4
实现这样的功能同时，页面没有感觉在刷新的感觉
是不是得用ajax??具体怎么实现的

解决方案 »

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使用2个downlist控件
下面有个XXback那个选项要点上勾
用ASP.NET AJAX是显,下面代码测试通过.
测试数据create table tddlTest
(
building int,
foor int
)insert tddlTest
select 1,1
union
select 1,2
union
select 1,3
union
select 1,4
union
select 2,1
union
select 2,2
union
select 2,6
页面代码<body>    <form id="form1" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <div>
        <br />
        <asp:DropDownList ID="ddlFirst" runat="server" AutoPostBack="True"
            onselectedindexchanged="ddlFirst_SelectedIndexChanged">
        </asp:DropDownList>
         DropDownList Test<br />
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:DropDownList ID="ddlSecond" runat="server">
                </asp:DropDownList>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="ddlFirst"
                    EventName="SelectedIndexChanged" />
            </Triggers>
        </asp:UpdatePanel>

    </div>
    </form>
</body>
后台代码using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;public partial class AjaxTest : System.Web.UI.Page
{    private const string conString = "Server=SZSOFT-SZZB\\SQLEXPRESS;database=office;uid=sa;pwd=abc_!123456;";    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            // 初始控件
            DataTable dt = GetFirstData();
            BindFirst(dt);
            ddlFirst_SelectedIndexChanged(null, null);
        }
    }    /// <summary>
    /// 选择改变
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ddlFirst_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (ddlFirst.SelectedItem != null)
        {
            DataTable dt = GetSecondData(ddlFirst.SelectedItem.Value);
            BindSecond(dt);
        }
    }    /// <summary>
    /// 绑定第一个下拉控件
    /// </summary>
    /// <param name="dt"></param>
    private void BindFirst(DataTable dt)
    {
        ddlFirst.DataTextField = "building";
        ddlFirst.DataValueField = "building";
        ddlFirst.DataSource = dt;
        ddlFirst.DataBind();
    }    /// <summary>
    ///  绑定第二个下拉控件
    /// </summary>
    /// <param name="dt"></param>
    private void BindSecond(DataTable dt)
    {
        ddlSecond.DataTextField = "foor";
        ddlSecond.DataValueField = "foor";
        ddlSecond.DataSource = dt;
        ddlSecond.DataBind();
    }    /// <summary>
    /// 获取数据
    /// </summary>
    /// <returns></returns>
    private DataTable GetFirstData()
    {
        SqlConnection con = new SqlConnection();
        con.ConnectionString = conString;
        con.Open();
        string sqlSelect = "Select building From tddlTest group by building";
        SqlDataAdapter adapter = new SqlDataAdapter(sqlSelect, con);
        DataTable dt = new DataTable();
        adapter.Fill(dt);
        return dt;
    }    /// <summary>
    /// 获取数据
    /// </summary>
    /// <returns></returns>
    private DataTable GetSecondData(string parentId)
    {
        SqlConnection con = new SqlConnection();
        con.ConnectionString = conString;
        con.Open();
        string sqlSelect = string.Format("Select foor From tddlTest where building='{0}'",parentId);
        SqlDataAdapter adapter = new SqlDataAdapter(sqlSelect, con);
        DataTable dt = new DataTable();
        adapter.Fill(dt);
        return dt;
    }}最后要却认下Web.config的<system.web>节点下有下面代码:<httpHandlers>
      <remove verb="*" path="*.asmx"/>
      <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
      <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
      <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>
    </httpHandlers>
    <httpModules>
      <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
    </httpModules>
<httpHandlers>
      <remove verb="*" path="*.asmx"/>
      <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
      <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
      <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>
    </httpHandlers>
    <httpModules>
      <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
    </httpModules>有什么作用
应该是初始化AJAX控件库吧，不然的话UpdatePanel 会报错
用UpdatePanel也有局部的刷新感觉哦
UpdatePanel里的东西刷新,跟服务器交互,刷新更新的内容,而不是提交整个页面.
如果你不跟服务器打交道,可以用javascript在页面实现.