protected void Page_Load(object sender, EventArgs e)
    {
        DataTable dt = "select id,name,Fid,LV from APP_Func".FSelect().FWhere("id<50 and LV<=4");
        DateTime ww = DateTime.Now;

        for (int i = 0; i < 10; i++)
        {
            RecursiveClass(dt, 0, "fid", dt.Clone()).FRepeater(this.Repeater1);
        }

        Label1.Text = "循环【10】次的时间 " + ww.FTDiff(DateTime.Now).ToString() + " 秒，总共" + dt.Rows.Count + "条数据";
    }
    /// <summary>
    /// [递归]无限级分类
    /// </summary>
    /// <param name="ddtt">有数据的datatable</param>
    /// <param name="id">起初的ID</param>
    /// <param name="Fid">id=父类字段名</param>
    /// <param name="dt">返回的DT数据</param>
    /// <returns></returns>
    public DataTable RecursiveClass(DataTable data, int id, string Fid, DataTable dt)
    {
        for (int i = 0; i < data.Rows.Count; i++)
        {
            if (!(Select(dt, "id=" + id.ToString(), "").Rows.Count > 0) && id != 0)
            {
                dt = Select(data, "id=" + id.ToString(), "");
            }
            if (int.Parse(data.Rows[i][Fid].ToString().Trim()) == id)
            {
                DataRow dr = dt.NewRow();
                string[] sd = new string[dt.Columns.Count];
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    sd[j] = data.Rows[i][dt.Columns[j].ToString()].ToString();
                }
                dr.ItemArray = sd;
                dt.Rows.Add(dr);
                RecursiveClass(data, int.Parse(data.Rows[i]["id"].ToString()), Fid, dt);
            }
        }
        return dt;
    }


    /// <summary>
    /// 执行DataTable中的查询返回新的DataTable
    /// </summary>
    /// <param name="dt">源数据DataTable</param>
    /// <param name="Where">查询条件【不需要加where】</param>
    /// <param name="Order">排序【不需要加Order by】</param>
    /// <returns>返回查询OK的DataTable</returns>
    public DataTable Select(DataTable dt, string Where, string Order)
    {
        DataTable newdt = new DataTable();
        newdt = dt.Clone();
        DataRow[] dr = dt.Select(Where, Order);
        for (int i = 0; i < dr.Length; i++)
        {
            newdt.ImportRow((DataRow)dr[i]);
        }
        return newdt;
    }