无限递归产品分类

PS:以前写过了的，这次整理下

namespace XR.Web
{
    using System;
    using System.Collections;
    using System.Configuration;
    using System.Data;
    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.Data.Sql;
    using System.Data.SqlClient;
    public partial class Default2 : System.Web.UI.Page
    {
        DataTable Tables = new DataTable();
        DataColumn DC = new DataColumn();
        DataRow DR;
        ProductCategoryBLL Category = new ProductCategoryBLL(); 
        protected void Page_Load(object sender, EventArgs e)
        {
            DataTable DT = Category.GetDataTable("YLProductCategory", 0);
            CreateDataTable();
            GetTree(DT, 0, 0);
            DropDownList1.DataSource = Tables;
            DropDownList1.DataTextField = "Title";
            DropDownList1.DataValueField = "ID";
            DropDownList1.DataBind();
        }
        public void GetTree(DataTable DT,int PID,int Depth)
        {
            DataView DV = DT.DefaultView;
            DV.RowFilter = "ParentID=" + PID;
            string str = string.Empty;
            if (Depth == 0)
            {
                str = "";           
            }
            else if (Depth == 1)
            {
                str = "├";
            }
            else
            {
                for (int i = 0; i < Depth; i++)
                {
                    str =str+"├" + "" + "-";
                }
            }
            foreach (DataRowView Drv in DV)
            {
                int ID = int.Parse(Drv["ID"].ToString());
                string Title = Drv["Title"].ToString();
                int ParentID = int.Parse(Drv["ParentID"].ToString());
                int Dep = int.Parse(Drv["Depth"].ToString());
                DR = Tables.NewRow();
                DR["ID"] = ID;
                DR["Title"] = str + Title;
                DR["ParentID"] = ParentID;
                DR["Depth"] = Dep;
                Tables.Rows.Add(DR);
                int n = Dep;
                n++;
                GetTree(DT,ID, n);
            }
        }
        public void CreateDataTable()
        {
            DC = new DataColumn();
            DC.ColumnName = "ID";
            DC.DataType = System.Type.GetType("System.Int32");
            Tables.Columns.Add(DC);

            DC = new DataColumn();
            DC.ColumnName = "Title";
            DC.DataType = System.Type.GetType("System.String");
            Tables.Columns.Add(DC);

            DC = new DataColumn();
            DC.ColumnName = "ParentID";
            DC.DataType = System.Type.GetType("System.Int32");
            Tables.Columns.Add(DC);

            DC = new DataColumn();
            DC.ColumnName = "Depth";
            DC.DataType = System.Type.GetType("System.Int32");
            Tables.Columns.Add(DC);
        }
    }

}