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Dynamic construction of the TreeView (Chinese Provinces and cities)

Source: Internet
Author: User
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The. aspx code is as follows:



<%@ page language= "C #" autoeventwireup= "true" codefile= "China urban District aspx.cs" inherits= "China urban District"%>


<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">


<title></title>
<body>
<form id= "Form1" runat= "Server" >
<div>

<asp:treeview id= "Tv_china" runat= "server" expanddepth= "0" > Notes:expanddepth= "0" means that the first node is closed all.
</asp:TreeView>
</div>
</form>
</body>

The. Aspx.cs code is as follows:

Using system;using system.collections.generic;using system.linq;using system.web;using System.Web.UI;using System.web.ui.webcontrols;using system.data.oledb;public partial class China City: system.web.ui.page{string str_cnn = "Pr ovider=microsoft.jet.oledb.4.0;    Data source= ";    String str_sourcefile = "~/data/china.mdb";    OleDbConnection CNN;    OleDbCommand cmd;    OleDbDataReader Datar;    String Str_sql; protected void Page_Load (object sender, EventArgs e) {if (!        IsPostBack) {maketree ();        }} protected void Maketree () {TreeNode _tnode, _parentnode;        String str_conn = str_cnn + MapPath (str_sourcefile);        CNN = new OleDbConnection (Str_conn); Cnn.        Open ();        Build a level (province) Str_sql = "Select P_id,p_name from T_province";        cmd = new OleDbCommand (Str_sql, CNN); Datar = cmd.        ExecuteReader (); while (Datar.            Read ()) {_tnode = new TreeNode (); _tnode. Text = Datar["P_name"].            ToString (); _tnode. Value= "P_" +datar["p_id"].            ToString (); Tv_china.                Nodes.Add (_tnode);        }//Build Level Two (city) str_sql = "Select C_id,c_name,c_pid from T_city";        cmd = new OleDbCommand (Str_sql, CNN); Datar = cmd.        ExecuteReader (); while (Datar. Read ()) {_parentnode = Tv_china. FindNode ("P_" + datar["C_pid"].            ToString ());//Find parent node _tnode = new TreeNode (); _tnode. Text = datar["C_name"].            ToString (); _tnode. Value = "C_" + datar["c_id"].            ToString (); _parentnode.childnodes.add (_tnode);//Added to parent node, used. Childnode method}//Build Level Three (zone) str_sql = "Select T_city.c_pid, t_city.c_id, t_district.d_id, T_district.d_n        Ame from T_district INNER JOIN t_city on t_district.d_cid = t_city.c_id ";        cmd = new OleDbCommand (Str_sql, CNN); Datar = cmd.        ExecuteReader (); while (Datar. Read ()) {_parentnode = Tv_china. FindNode ("P_" + datar["C_pid"]. TOstring () + "/c_" + datar["c_id"].            ToString ());            _tnode = new TreeNode (); _tnode. Text = datar["D_name"].            ToString (); _tnode. Value = "D_" + datar["d_id"].            ToString ();        _parentnode.childnodes.add (_tnode); } CNN.        Close (); }}

The effect is as follows:


The following section describes the method of local refresh, considering that this method occupies a more serious system resource.

Dynamic construction of the TreeView (Chinese Provinces and cities)

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
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