DropDrownList控件递归绑定数据

现将表中的字段封装成属性：文件名（Demo_Area.cs）

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

/// <summary>
///Demo_Area 的摘要说明
/// </summary>
public class Demo_Area
{
 public Demo_Area()
 {
  //
  //TODO: 在此处添加构造函数逻辑
  //
 }
    private int id;
    private string name;
    private int pid;

    public int Pid
    {
        get { return pid; }
        set { pid = value; }
    }

    public string Name
    {
        get { return name; }
        set { name = value; }
    }

    public int Id
    {
        get { return id; }
        set { id = value; }
    }

}

页面中的代码段：

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

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

   //连接数据库
    private static string connstr = System.Configuration.ConfigurationManager.ConnectionStrings["ConnStr"].ToString();
    private static int intFlag;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (IsPostBack)
            return;
        Demo_Area da = new Demo_Area();
        da.Pid = 0;
        BindCountry(da);

    }
   
    #region 递归绑定国家和地区
    private void BindCountry(Demo_Area parma)
    {
        DataSet ds = BindCity(parma);
        if (ds.Tables[0].Rows.Count <= 0)
            return;
        intFlag++;
        int i = 0;
        for (; i < ds.Tables[0].Rows.Count; i++)
        {
            Demo_Area area = new Demo_Area();
            area.Name = ds.Tables[0].Rows[i]["Name"].ToString();
            area.Id = Convert.ToInt32(ds.Tables[0].Rows[i]["Id"].ToString());
            BindDDL(area);
            area.Pid = Convert.ToInt32(ds.Tables[0].Rows[i]["Id"].ToString());
            BindCountry(area);
        }
        if (ds.Tables[0].Rows.Count <= i)
            intFlag--;
    }
    #endregion

    #region 绑定DropDrownList
    private void BindDDL(Demo_Area parma)
    {
        string temp = "";
        for (int i = 0; i < intFlag - 2; i++)
        {
            temp += "　┃";
        }
        if (intFlag != 1)
            temp += "　┣";
        temp += parma.Name;
        DropDownList1.Items.Add(new ListItem(temp, parma.Id.ToString()));

    }
    #endregion

    #region  查询数据并返回一张虚拟表
    private DataSet BindCity(Demo_Area param)
    {
        SqlConnection con = new SqlConnection(connstr);
        con.Open();
        string strSQL = "select * from Area_MS where Pid=" + param.Pid;
        SqlDataAdapter sda = new SqlDataAdapter(strSQL, con);
        DataSet ds = new DataSet();
        sda.Fill(ds);
        return ds;
    }

    #endregion

效果图：