Asp. The method and related source of the TreeView and database binding in net

These days always see csdn someone asked the TreeView and database binding problem, just these days also made a this thing. There is also a TreeView-speaking article on the internet, but the search is on that one, and it is associated with access.
Here's how to implement it. The following are the implementation effects.
Step One: vs Web Development does not have the TreeView control, so first to the Microsoft website (http://msdn.microsoft.com/downloads/samples/internet/ASP_DOT_NET_ServerControls/
webcontrols/default.asp) go up and down the control, the site has a specific installation method, only the installation completed to use this control.
The second step: Database design
Look directly at the screenshot. The following is the design of the database.
Below is the value inside the database.
The following is the code, mainly using recursive algorithms to add the node to the TreeView. Using System;
Using System.Collections;
Using System.ComponentModel;
Using System.Data;
Using System.Drawing;
Using System.Web;
Using System.Web.SessionState;
Using System.Web.UI;
Using System.Web.UI.WebControls;
Using System.Web.UI.HtmlControls;
Using Microsoft.Web.UI.WebControls;
Using System.Data.SqlClient;
Using System.Configuration;
Namespace Testonline.treeview
... {
/**////<summary>
Summary description of the treeView1.
</summary>
public class TreeView1:System.Web.UI.Page
... {
protected System.Web.UI.WebControls.DataGrid DataGrid1;
protected System.Web.UI.WebControls.TextBox TextBox1;
protected System.Web.UI.WebControls.CheckBox CheckBox1;
protected System.Web.UI.WebControls.Button Button1;
protected Microsoft.Web.UI.WebControls.TreeView TreeView3;
public static string Url= "Workstation Id=all;packet size=4096; uid=sa;password=;d ata source= (local);p the ersist security info=true;initial catalog=testonline; Max Pool size=500; Min Pool size=5 ";
Public SqlConnection myconnection=new SqlConnection (URL);
private void Page_Load (object sender, System.EventArgs e)
... {
Place user code here to initialize page

Try
... {

Myconnection.open ();
SqlDataAdapter Sda=new SqlDataAdapter ("select * from Tbtree", MyConnection);
DataSet ds=new DataSet ();
Sda. Fill (DS);
This. viewstate["DS"]=DS;
}
catch (Exception ex)
... {
Console.Write (ex);
Response.Redirect ("Login.aspx");
}
Finally
... {
Myconnection.close ();
}
Addtree ("0", (TreeNode) null);

}
Web Forms Designer generated Code #region Web Forms Designer generated code
Override protected void OnInit (EventArgs e)
... {
//
CodeGen: This call is required for the ASP.net Web forms Designer.
//
InitializeComponent ();
Base. OnInit (e);
}

/**////<summary>
Designer supports required methods-do not use the Code editor to modify
The contents of this method.
</summary>
private void InitializeComponent ()