动态生成DropDownList 并取值

时间：2023-03-09 23:07:40
动态生成DropDownList 并取值

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>  

<!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>无标题页</title>

</head>

<body>

    <form id="form1" runat="server">

    <div>

        <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>

        <br />

        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" /></div>

    </form>

</body>

</html>

Default.aspx.cs

using System;

using System.Data;

using System.Configuration;

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 Model;

using BLL;  

public partial class _Default : System.Web.UI.Page

{

    private CategoryBLL _categoryBLL = new CategoryBLL();

    private Category _category = new Category();  

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

    {

        BindDrpClass();

    }

    protected void Page_Load(object sender, EventArgs e)

    {

        string str = "8/14/19/25"; //数据库读取

        string[] arr = str.Split('/');

        if (arr.Length == PlaceHolder1.Controls.Count) //防止新增类别时读取出错

        {

            for (int i = ; i < PlaceHolder1.Controls.Count; i++)

            {

                if (PlaceHolder1.Controls[i] is DropDownList)

                {

                    ((DropDownList)PlaceHolder1.Controls[i]).SelectedValue = arr[i];

                }

            }

        }

    }  

    private void BindDrpClass()

    {

        DataTable dt = _categoryBLL.GetCategory();

        DataRow[] drs = dt.Select("pid=0");  

        foreach (DataRow dr in drs)

        {

            string id = dr["id"].ToString();

            string name = dr["name"].ToString();  

            DropDownList ddl = new DropDownList();

            ddl.Items.Clear();

            ddl.ID = "ddl" + id;

            ddl.Items.Add(new ListItem("－" + name + "－", id));

            PlaceHolder1.Controls.Add(ddl);  

            int sonparentid = int.Parse(id);

            BindDrpNode(sonparentid, dt, ddl);

        }  

    }  

    private void BindDrpNode(int parentid, DataTable dt, DropDownList ddl)

    {

        DataRow[] drs = dt.Select("pid= " + parentid);

        foreach (DataRow dr in drs)

        {

            string id = dr["id"].ToString();

            string name = dr["name"].ToString();  

            ddl.Items.Add(new ListItem(name, id));

            PlaceHolder1.Controls.Add(ddl);

        }

    }

    protected void Button1_Click(object sender, EventArgs e)

    {

        string category = "";

        string category2 = "";

        foreach (Control childControl in PlaceHolder1.Controls)

        {

            if (childControl is DropDownList)

            {

                category += "/" + ((DropDownList)childControl).SelectedItem.Text;

                category2 += "/" + ((DropDownList)childControl).SelectedValue;

            }

        }

        if (category.Length > )

            category = category.Remove(, );

        Response.Write(category);  

        Response.Write("<br />");  

        if (category2.Length > )

            category2 = category2.Remove(, );

        Response.Write(category2);

    }

}

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