How to validate the text when renaming the tree node in EJ2 JavaScript TreeView

4 Sep 20268 minutes to read

You can validate the text of a tree node while it is being edited by using the nodeEditing event of the TreeView control. This event fires before the edit is committed and supports cancellation via args.cancel, which makes it the recommended event for preventing invalid values (such as empty text) from being saved. The nodeEdited event, by contrast, fires only after the edit has been applied. The following example demonstrates how to validate and prevent empty values in a tree node using the nodeEditing event.

ej.base.enableRipple(true);

/**
 * TreeView node editing sample with validation
 */

// Hierarchical data source for TreeView control
var treeData = [
    {
        id: 1, name: 'Discover Music', expanded: true,
        child: [
            { id: 2, name: 'Hot Singles' },
            { id: 3, name: 'Rising Artists' },
            { id: 4, name: 'Live Music' }
        ]
    },
    {
        id: 7, name: 'Sales and Events',
        child: [
            { id: 8, name: '100 Albums - $5 Each' },
            { id: 9, name: 'Hip-Hop and R&B Sale' },
            { id: 10, name: 'CD Deals' }
        ]
    },
    {
        id: 11, name: 'Categories',
        child: [
            { id: 12, name: 'Songs' },
            { id: 13, name: 'Bestselling Albums' },
            { id: 14, name: 'New Releases' },
            { id: 15, name: 'Bestselling Songs' }
        ]
    },
    {
        id: 16, name: 'MP3 Albums',
        child: [
            { id: 17, name: 'Rock' },
            { id: 18, name: 'Gospel' },
            { id: 19, name: 'Latin Music' },
            { id: 20, name: 'Jazz' }
        ]
    },
    {
        id: 21, name: 'More in Music',
        child: [
            { id: 22, name: 'Music Trade-In' },
            { id: 23, name: 'Redeem a Gift Card' },
            { id: 24, name: 'Band T-Shirts' }
        ]
    }
];

// Render the TreeView with editing option
var treeObj = new ej.navigations.TreeView({
    fields: { dataSource: treeData, id: 'id', text: 'name', child: 'child' },
    allowEditing: true,
    nodeEdited: onNodeEdited
});
treeObj.appendTo('#tree');

function onNodeEdited(args) {
    var displayContent = "";
    if (args.newText.trim() == "") {
        args.cancel = true;
        displayContent = "TreeView item text should not be empty";
    }
    else if (args.newText != args.oldText) {
        displayContent = "TreeView item text edited successfully";
    } else {
        displayContent = "";
    }
    document.getElementById("display").innerHTML = displayContent;
}
<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="https://cdn.syncfusion.com/ej2/34.2.2/ej2-base/styles/bootstrap5.3.css" rel="stylesheet">
  <link href="https://cdn.syncfusion.com/ej2/34.2.2/ej2-inputs/styles/bootstrap5.3.css" rel="stylesheet">
  <link href="https://cdn.syncfusion.com/ej2/34.2.2/ej2-navigations/styles/bootstrap5.3.css" rel="stylesheet">
  <script src="https://cdn.syncfusion.com/ej2/34.2.2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
  <div id="container">
    <div id="treeparent">
      <div id="tree"></div>
      <div id="display"></div>
    </div>
  </div>

  <script>
    var ele = document.getElementById('container');
    if (ele) {
      ele.style.visibility = "visible";
    }   
  </script>
  <script src="index.js" type="text/javascript"></script>
  <style>
    #treeparent {
      display: block;
      max-width: 350px;
      max-height: 350px;
      margin: auto;
      overflow: auto;
      border: 1px solid #dddddd;
      border-radius: 3px;
    }

    #display {
      max-width: 500px;
      margin: auto;
      padding: 10px;
    }
  </style>
</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%;
}