本文實例講述了asp.net實現遞歸方法取出菜單并顯示在DropDownList中的方法。分享給大家供大家參考，具體如下：
樹形欄目展示以DropDownList的形式顯示出來。
protected void Page_Load(object sender, EventArgs e){ if (!IsPostBack) { DataTable table = bllSite.GetChannelNames(CurrentUser.ParkID); BindChannelType(table, 0, 0); }}//遞歸方法取private void BindChannelType(DataTable dt, int categoryid, int layer){ DataView dv = new DataView(dt); dv.RowFilter = " Pid= " + categoryid.ToString(); //過濾 if (categoryid != 0) { layer++; //默認為第一層 } foreach (DataRowView drv in dv) { string span = ""; if (categoryid != 0) { for (int i = 0; i < layer; i++)//父級菜單不縮進 { span += " "; } span += "└"; } ListItem li = new ListItem(); li.Text = span + drv["ChannelName"].ToString(); li.Value = drv["Id"].ToString(); this.ddlChannel.Items.Add(li); BindChannelType(dt, Convert.ToInt32(drv["Id"]), layer); }} 
