You can sort the TreeView nodes based on their level. When using the sortOrder property, the whole TreeView is sorted. When you sort a particular level, you can use the following code sample. The following code sample demonstrates how to sort the parent node alone in TreeView.
/**
* Accordion tree sample
*/
// Hierarchical data source for TreeView component
var countries = [
{ id: 1, name: 'India', hasChild: true },
{ id: 2, pid: 1, name: 'Assam' },
{ id: 3, pid: 1, name: 'Bihar' },
{ id: 4, pid: 1, name: 'Tamil Nadu' },
{ id: 6, pid: 1, name: 'Punjab' },
{ id: 7, name: 'Brazil', hasChild: true },
{ id: 8, pid: 7, name: 'Paraná' },
{ id: 9, pid: 7, name: 'Ceará' },
{ id: 10, pid: 7, name: 'Acre' },
{ id: 11, name: 'France', hasChild: true },
{ id: 12, pid: 11, name: 'Pays de la Loire' },
{ id: 13, pid: 11, name: 'Aquitaine' },
{ id: 14, pid: 11, name: 'Brittany' },
{ id: 15, pid: 11, name: 'Lorraine' },
{ id: 16, name: 'Australia', hasChild: true },
{ id: 17, pid: 16, name: 'New South Wales' },
{ id: 18, pid: 16, name: 'Victoria' },
{ id: 19, pid: 16, name: 'South Australia' },
{ id: 20, pid: 16, name: 'Western Australia' },
{ id: 21, name: 'China', hasChild: true },
{ id: 22, pid: 21, name: 'Guangzhou' },
{ id: 23, pid: 21, name: 'Shanghai' },
{ id: 24, pid: 21, name: 'Beijing' },
{ id: 25, pid: 21, name: 'Shantou' }
];
var tree1 = new ej.navigations.TreeView({
fields: { dataSource: countries, id: 'id', text: 'name', parentID: 'pid', hasChildren: 'hasChild' },
created: onCreate,
nodeExpanding: onNodeExpand
});
tree1.appendTo('#tree');
function changeDataSource(data) {
tree1.fields = {
dataSource: data, id: 'id', text: 'name', parentID: 'pid', hasChildren: 'hasChild'
}
}
var newData;
function onCreate(){
newData = this.fields.dataSource;
// Selects the first level nodes alone
var resultData= new ej.data.DataManager(this.getTreeData()).executeLocal(new ej.data.Query().where(this.fields.parentID, 'equal', undefined, false));
var name= [];
for (var i = 0; i < resultData.length; i++){
name.push(resultData[i][this.fields.text]);
}
name.sort();
var arr = [];
for (var j = 0; j < name.length; j++) {
var sortedData = new ej.data.DataManager(this.getTreeData()).executeLocal(new ej.data.Query().where(this.fields.text, 'equal', name[j], false));
var childData = new ej.data.DataManager(newData).executeLocal(new ej.data.Query().where(this.fields.parentID, 'equal', parseInt(sortedData[0][this.fields.id]), false));
arr.push(sortedData[0]);
}
// Renders treeview with sorted Nodes
changeDataSource(arr);
tree1.dataBind();
}
function onNodeExpand(args){
if (args.isInteracted && args.node.querySelector('li') === null){
var childData = new ej.data.DataManager(newData).executeLocal(new ej.data.Query().where(this.fields.parentID, 'equal', parseInt(args.nodeData.id), false));
tree1.addNodes(childData, args.node,null)
}
}<!DOCTYPE html><html lang="en"><head>
<title>Essential JS 2 for TreeView </title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Essential JS 2 for TreeView UI Control">
<meta name="author" content="Syncfusion">
<link href="index.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/21.2.3/ej2-base/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/21.2.3/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="//cdn.syncfusion.com/ej2/21.2.3/ej2-navigations/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/21.2.3/dist/ej2.min.js" type="text/javascript"></script>
</head>
<body>
<div id="container">
<div id="treeparent">
<div id="tree"></div>
</div>
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>#container {
visibility: hidden;
}
#loader {
color: #008cff;
height: 40px;
width: 30%;
position: absolute;
font-family: 'Helvetica Neue','calibiri';
font-size: 14px;
top: 45%;
left: 45%;
}
#treeparent {
display: block;
max-width: 350px;
max-height: 350px;
margin: auto;
overflow: auto;
border: 1px solid #dddddd;
border-radius: 3px;
}