使用DropDownList控件实现无限级分类绑定

     <asp:DropDownList ID="AreaList" runat="server" Width="180px">
                            </asp:DropDownList></td>


  #region 绑定DropDownList（无限极分类）
    public void Bind()
    {
        dv = new DataView(tm.GetClass());
        dv.Sort = STR_PARENTID;
        string schar = STR_TREENODE;
        if (dv.Table.Rows.Count > 0)
        {
            RecursBind(-1, ref schar);
        }
    } 
    #endregion

    #region 递归绑定DropDownList（无限极分类）
    private void RecursBind(int pid, ref string schar)
    {
        if (pid == -1)
        {
            AreaList.Items.Add(new ListItem("添加一级分类", "0"));
            foreach (DataRow row in dv.Table.Rows)
            {
                if (Convert.ToInt32(row[STR_ID]) == Convert.ToInt32(row[STR_PARENTID]))
                {                                  
                    this.AreaList.Items.Add(new ListItem("╋" + row[STR_DISPLAYNAME].ToString(), row[STR_ID].ToString()));
                    RecursBind(Convert.ToInt32(row[STR_ID]), ref schar);
                }