如何制作动态三级下拉菜单

Question

请教各位   asp.net 如何制作动态三级下拉菜单

Answer 1

protected void ddlProfession1_SelectedIndexChanged(object sender, EventArgs e)
    {
        switch (ddlProfession1.SelectedValue)
        {
            case "IT":
                {
                    ddlProfession2.Items.Clear();
                    ddlProfession2.Items.Insert(0,"网络安全");
                    ddlProfession2.Items.Insert(1, "入侵检测");
                }
                break;
            case "医疗":
                {
                    ddlProfession2.Items.Clear();
                    ddlProfession2.Items.Insert(0,"中医针灸");
                    ddlProfession2.Items.Insert(1, "中医理疗");
                }
                break;
        }
    }
//这种做法行不

Answer 2

CSS二级横向菜单,三级下拉菜单五款(纯CSS)
自己去选！！！

Answer 3

http://www.open-open.com/ajax/ajax20080824230840.htm

Answer 4

Ajax 三级联动 实现分类 .NET/C#  2010-08-13 11:35:12|  分类： .NET/C# 
|字号
 订阅
通过控件拖动实现：
 <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <br />
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <table style="width:100%;">
                <tr>
                    <td class="style1">
                        一级：<asp:DropDownList ID="ddl" runat="server" AppendDataBoundItems="True" DataTextField="name" DataValueField="id" 
                           OnSelectedIndexChanged="changeFirst" AutoPostBack="true">
                                <asp:ListItem>--请选择--</asp:ListItem>
                        </asp:DropDownList>
                    </td>
                    <td class="style2">
                        二级：<asp:DropDownList ID="ddl2" runat="server" AppendDataBoundItems="True" DataTextField="name" DataValueField="id" 
                           OnSelectedIndexChanged="changeSecond" AutoPostBack="true">
                                <asp:ListItem>--请选择--</asp:ListItem>
                        </asp:DropDownList>
                    </td>
                    <td>
                        三级：<asp:DropDownList ID="ddl3" runat="server" DataTextField="name" DataValueField="id" >
                        </asp:DropDownList>
                    </td>
                </tr>
            </table>
        </ContentTemplate>
后台CS代码
public partial class Publish_Default2 : System.Web.UI.Page
{
   // int pageNo = 1;
   // int pageSize = 999;
    //PageModel pageModel = new PageModel();
  private string ConnectionString = ConfigurationManager.ConnectionStrings["ConString"].ToString();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            this.bindDDL();
        }
    }    private void bindDDL()
    {
        SqlConnection conn = new SqlConnection(ConnectionString);
        string sql = "select id,name,parentid from category where parentid="+0;//0代表一级分类
         SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
         DataTable dt = new DataTable();
         adapter.Fill(dt);
       
        this.ddl.DataSource = dt.DefalultView;
        this.ddl.DataBind();
    }
    protected void changeFirst(object sender, EventArgs e)
    {
        int id = Convert.ToInt32(ddl.SelectedValue);
       SqlConnection conn = new SqlConnection(ConnectionString);
        string sql = "select id,name,parentid from category where parentid="+id;
        SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
         DataTable dt = new DataTable();
         adapter.Fill(dt);
       
        this.ddl2.DataSource = dt.DefalultView;//这个语句是追加语句，不是将ddl2中以前的数据删除，而是追加。
   
        ddl2.Items.Clear();//此项很重要，主要是删除ddl2中已经存在的数据，
        this.ddl2.Items.Add("---请选择---");
        ddl2.DataBind();    }
    protected void changeSecond(object sender, EventArgs e)
    {
        int id = Convert.ToInt32(ddl2.SelectedValue);
        SqlConnection conn = new SqlConnection(ConnectionString);
        string sql = "select id,name,parentid from category where parentid="+id;
        SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
         DataTable dt = new DataTable();
         adapter.Fill(dt);
       
        this.ddl2.DataSource = dt.DefalultView;/
        ddl3.Items.Clear();
        ddl3.DataBind();
    }}Category表结构  
id int 
name varchar
parentid int   

Answer 5

Ajax 三级联动 实现分类 .NET/C#  2010-08-13 11:35:12|  分类： .NET/C# 
|字号
 订阅
通过控件拖动实现：
 <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <br />
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <table style="width:100%;">
                <tr>
                    <td class="style1">
                        一级：<asp:DropDownList ID="ddl" runat="server" AppendDataBoundItems="True" DataTextField="name" DataValueField="id" 
                           OnSelectedIndexChanged="changeFirst" AutoPostBack="true">
                                <asp:ListItem>--请选择--</asp:ListItem>
                        </asp:DropDownList>
                    </td>
                    <td class="style2">
                        二级：<asp:DropDownList ID="ddl2" runat="server" AppendDataBoundItems="True" DataTextField="name" DataValueField="id" 
                           OnSelectedIndexChanged="changeSecond" AutoPostBack="true">
                                <asp:ListItem>--请选择--</asp:ListItem>
                        </asp:DropDownList>
                    </td>
                    <td>
                        三级：<asp:DropDownList ID="ddl3" runat="server" DataTextField="name" DataValueField="id" >
                        </asp:DropDownList>
                    </td>
                </tr>
            </table>
        </ContentTemplate>
后台CS代码
public partial class Publish_Default2 : System.Web.UI.Page
{
   // int pageNo = 1;
   // int pageSize = 999;
    //PageModel pageModel = new PageModel();
  private string ConnectionString = ConfigurationManager.ConnectionStrings["ConString"].ToString();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            this.bindDDL();
        }
    }    private void bindDDL()
    {
        SqlConnection conn = new SqlConnection(ConnectionString);
        string sql = "select id,name,parentid from category where parentid="+0;//0代表一级分类
         SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
         DataTable dt = new DataTable();
         adapter.Fill(dt);
       
        this.ddl.DataSource = dt.DefalultView;
        this.ddl.DataBind();
    }
    protected void changeFirst(object sender, EventArgs e)
    {
        int id = Convert.ToInt32(ddl.SelectedValue);
       SqlConnection conn = new SqlConnection(ConnectionString);
        string sql = "select id,name,parentid from category where parentid="+id;
        SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
         DataTable dt = new DataTable();
         adapter.Fill(dt);
       
        this.ddl2.DataSource = dt.DefalultView;//这个语句是追加语句，不是将ddl2中以前的数据删除，而是追加。
   
        ddl2.Items.Clear();//此项很重要，主要是删除ddl2中已经存在的数据，
        this.ddl2.Items.Add("---请选择---");
        ddl2.DataBind();    }
    protected void changeSecond(object sender, EventArgs e)
    {
        int id = Convert.ToInt32(ddl2.SelectedValue);
        SqlConnection conn = new SqlConnection(ConnectionString);
        string sql = "select id,name,parentid from category where parentid="+id;
        SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
         DataTable dt = new DataTable();
         adapter.Fill(dt);
       
        this.ddl2.DataSource = dt.DefalultView;/
        ddl3.Items.Clear();
        ddl3.DataBind();
    }}Category表结构  
id int 
name varchar
parentid int   

Answer 6

http://mesky.net/downz/tkiekhe给你一个demo