asp.net 2.0 to implement the Treeview binding with the database (with code)

asp.net 2.0 to implement the Treeview binding with the database (with code)

Programming Ideas:

Each record represents a node. The logical hierarchical relationship is formed by the F_nodeid and F_parentnodeid of the 2 digital core fields in the table. The contract 0 represents the root node. Other fields are secondary fields and are not related to this article.

Define and initialize an object array mynodes, and then read the records in the table at once, establishing all the subordinate relationships by determining the parent node of the current node.

Sample data:

Run Result:

Sample Downloads: Http://www.why100000.com/_ftps/samples/Tree+db.rar

(Code Debugging Environment: Visual Web Developer, Edition Express)

Access database name: Db_system.mdb

Table Name: TabItems

Table structure:

F_i_autoid Automatic Numbering

F_nodeid number (this node ID)

F_parentnodeid Number (parent node ID)

F_name text

F_tag text

F_url text

F_order Digital

F_ishidden text

F_datetime Date/Time

Key code:

Using System;

Using System.Data;

Using System.Data.OleDb;

Using System.Configuration;

Using System.Web;

Using System.Web.Security;

Using System.Web.UI;

Using System.Web.UI.WebControls;

Using System.Web.UI.WebControls.WebParts;

Using System.Web.UI.HtmlControls;

public partial class _default:system.web.ui.page

{

protected void Page_Load (object sender, EventArgs e)

{

if (! IsPostBack)

{

String sDBPath = "./db_system.mdb"; //"

String spassword = "";

String sdbtable = "TabItems";

OleDbConnection oconn = new OleDbConnection ("Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + Server.MapPath (SDbPath) + "; Password= "+ Spassword +"; ");

OleDbDataReader oDr;

Try

{

oConn.Open ();

OleDbCommand ocmd = new OleDbCommand ("SELECT * from" + sdbtable, oconn); + "ORDER by F_level"

ODr = Ocmd.executereader ();

Defining an array of objects

treenode[] Mynodes = new treenode[100];

Initializing an array of objects

for (int i = 0; i < mynodes.length; i++)

{

Mynodes[i] = new TreeNode ();

}

Fetching data from a table

while (Odr.read ())

{

int iparentnodeid = (int) odr["F_parentnodeid"];

int imynodeid = (int) odr["F_nodeid"];

if (Iparentnodeid!= 0)

{

Mynodes[imynodeid]. Text = odr["F_name"]. ToString ();

Mynodes[imynodeid]. NavigateUrl = odr["F_url"]. ToString ();

Mynodes[iparentnodeid]. Childnodes.add (Mynodes[imynodeid]);

}

Else

{

Mynodes[imynodeid]. Text = odr["F_name"]. ToString ();

Mynodes[imynodeid]. SelectAction = Treenodeselectaction.none;

TREEVIEW1.NODES.ADD (Mynodes[imynodeid]);

}

}

}

catch (System.Exception Sqle)

{

Sqle. ToString (). Replace ("n", "<br>");

Response.Write (Sqle);

}

Finally

{

Oconn.close ();

}

}

}

}

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My other articles are on my personal website:
"100,000 Why" computer Learning Network: http://www.why100000.com

        Zhang Qing zhangking@hotmail.com,qq:9365822
         http://why100000.com
        http://sogo99.com
         2006.1.10