“递归”实现无限级分类
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
public partial class _Default : System.Web.UI.Page
{
AccessHelper helper = new AccessHelper();
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
helper.CreateCommand("select * from category");
GridView1.DataSource = helper.ExecuteQuery();
GridView1.DataBind();
helper.CreateCommand("select * from category where pid=0");
DataTable dt_topca = helper.ExecuteQuery(); // 选择所有顶级分类
string html = "<ul>\n";
foreach (DataRow row in dt_topca.Rows)
{
html += "<li>\n";
html += row["caname"].ToString() + "\n";
AddChildCa(row["id"].ToString(), ref html); // 递归添加子分类，用ref传html字符串的地址进去
html += "</li>\n";
}
html += "</ul>\n";
litHTML.Text = html;
}
}
// 递归添加子分类，用ref传html字符串的地址进去
private void AddChildCa(string pid, ref string html)
{
html += "<ul>\n";
helper.CreateCommand("select * from category where pid=" + pid);
DataTable dt_subca = helper.ExecuteQuery();
foreach (DataRow row in dt_subca.Rows)
{
html += "<li>\n";
html += row["caname"].ToString() + "\n";
AddChildCa(row["id"].ToString(), ref html); // 递归添加子分类，用ref传html字符串的地址进去
html += "</li>\n";
}
html += "</ul>\n";
}
}
页面代码：
<%@ 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></title>
</head>
<body>
<form id="form1" runat="server">
<div style="font-weight: bold; color: Red;">
数据库中的数据：
</div>
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
<hr />
<div style="font-weight: bold; color: Blue;">
递归生成HTML标记：
</div>
<asp:Literal ID="litHTML" runat="server"></asp:Literal>
</form>
</body>
</html>
