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ASP TreeList Control (Requires Internet Explorer 5.0+)

, 21 Apr 2002
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An ASP class (Classic ASP) that generates a dynamic html tree list control that looks the same as a windows explorer tree but allows multiple columns of data per tree node
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Sample Image - asptreelistcontrol.gif

<!-- Add the rest of your HTML here -->


I needed a class to create a tree list control for a web application I'm building, and after looking around on the net and failing to find anything similar, I decided to create my own. The main challenge with creating a decent tree list control with HTML, CSS and JScript is that there is no way to effectively create a node heirarchy and guarantee that the columns for each node will line up with the columns for all the other nodes. I experimented with div, span, table, tbody, thead, tr, p, ul, etc, but none offered an acceptable solution.

My solution was to create a single non-heirarchical table and store all of the node information in a javascript array. When a +/- button is pressed, the javascript extrapolates from the array which rows it has to hide and which nodes it has to show. Note that doing it this way I also had to store state information for every expandable node so that when expanding or collapsing a node, it would maintain the expanded/collapsed state of child nodes.

The ASP class generates an initial tree and the JScript code reads the html and extracts the information it needs to make the tree interactive. Unfortunately you can't update the tree with the current code once it has been generated in the browser, but that is ok because I had no need to do that.

My MAIN issue with this tree list control is, although it is reasonably fast to generate, and works perfectly, after you get about 100-200 nodes in the tree (I'm using a Pentium 4, 1.4ghz), the JScript starts getting very slow and unresponsive. If you find this control useful and manage to optimise the jscript code so that it is actually fast with a large number of nodes in the tree, I would greatly appreciate it if you could post the updated code here so I can take a look.

Below is the code to create a demonstration tree list. As you can see the control is very easy to use, just create an instance of the control, add the column headings, and then add the nodes. You can't add a node if its parent doesn't yet exist. Also, you should not reveal a node using the reveal function unless the node actually exists. Doing so will cause the page to create an error.

<!--<span class="code-comment">#include file="treelistcontrol/treelistcontrol.asp"--></span>
	dim tree
	set tree = new treelistcontrol

	'specify our default settings for the tree
	tree.allowrowselect = false
	tree.showborder = false
	tree.pathtoicons = "treelistcontrol/"
	tree.showdividers = false

	'define the columns for the tree
	tree.addcolumn "Node Name", "", ""
	tree.addcolumn "Day of Week", "100", ""
	tree.addcolumn "Month", "100", ""
	tree.addcolumn "Random Number", "80", "right"
	dim id, parentid, theday, themonth, thenumber
	for id = 1 to 100
		'make some random values for the tree
		parentid = int(rnd*id)
		theday = weekdayname(int(rnd*7)+1)
		themonth = monthname(int(rnd*12)+1)
		thenumber = formatnumber(int(rnd*1000000),,,true)
		'add the node
		tree.addnode id+0, parentid, "treelistcontrol/icon_folder.gif", false, _
				array(id+0, theday, themonth, thenumber)
	'reveal node #100
	tree.revealnode 100
	response.write tree.value


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

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About the Author

Nathan Ridley
Web Developer
Australia Australia
Web application developer, graphic designer, aspiring entrepreneur, snowboarder and electronic music afficianado.

Comments and Discussions

GeneralRe: i need help in use this code to display tree folder PinmemberNathan Ridley26-Apr-03 15:26 
GeneralMAC Explorer 5.0+ PinsussBelse30-Jan-03 7:27 
GeneralRe: MAC Explorer 5.0+ PinmemberNathan Ridley30-Jan-03 11:19 
GeneralMuch faster way of expanding nodes PinsussAnonymous29-Dec-02 6:53 
There is a much faster way of expanding and collapsing nodes. When a click event is fired, you can get the rowindex of the row it was fired on. Then you can access the rows collection of tha table and descend from the clicked node looking for children to show or hide, exiting when you are no longer at the same level.
Here is a basic example and I've tested this on a tree table with 2000 nodes and it is instantaneous.
String.prototype.contains = function(parMatch, blnCaseSensitive) {
var retVal = false;
var strMatch = String(parMatch);

if (strMatch.length == 0)
return true; //per XPath spec

blnCaseSensitive = blnCaseSensitive | (String(blnCaseSensitive) == 'undefined');

if (blnCaseSensitive)
retVal = (this.indexOf(strMatch) > -1);
retVal = (this.toUpperCase().indexOf(strMatch.toUpperCase()) > -1)
return retVal;
function countItems(_str,_del)
return _str.split(_del).length;


function treelistcontrol_showhide(obj,tlc_id){

var trObj;
var tableObj;
var bEnd;
var currentRowIndex;
var currentRowObj;
Eek! | :eek:

tableObj = document.getElementById('treelistctrl' + tlc_id);

// get the row object
trObj = obj.parentElement.parentElement;
trObjId =;
currentRowIndex = trObj.rowIndex;
levelId = countItems(trObjId,"_");
bEnd = false;
rowCount = 0;
do {
if (rowCount > 100) { // this can be taken out for testing
bEnd = true;

// get the row
currentRowObj = tableObj.rows(currentRowIndex);

// see if the row is a generation of the parent
rowId =

rowIdString = rowId.toString();

if (rowIdString.contains(trObjId,false) && (countItems(rowIdString,"_") == (levelId + 1))) { "";
} else {
// There are no more children
bEnd = true;

while (!bEnd)

GeneralRe: Much faster way of expanding nodes PinsussAnonymous29-Dec-02 13:26 
GeneralRe: Much faster way of expanding nodes Pinmembery1091330-May-03 7:25 
GeneralRe: Much faster way of expanding nodes Pinmembermgcristino14-Sep-04 0:28 
GeneralGenerate treeview in html page PinmemberJob523-Dec-02 0:46 
GeneralRe: Generate treeview in html page Pinmemberx_sjb17-Feb-03 19:00 
GeneralRe: Generate treeview in html page PinmemberNathan Ridley18-Feb-03 10:28 

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