Asynchronously Clone TreeView Nodes and All Their Children

Updated on Dec 10, 2025

Environment

Product Version	2018.2.516
Product	Progress® Kendo UI® TreeView for jQuery

Description

How can I copy a TreeView node along with all its children when loadOnDemand is set to true?

Solution

Asynchronously load the child nodes in the child data source by using the load() method of the node.

<div id="content">
    <button id="cloneNode" class="k-button k-primary">Clone selected node and append it to the TreeView</button>
    <div id="treeview"></div>
</div>

<script>
$(document).ready(function() {
    var homogeneous = new kendo.data.HierarchicalDataSource({
        transport: {
            read: {
                url: "https://demos.telerik.com/service/v2/core/Employees"
            }
        },
        schema: {
            model: {
                id: "EmployeeId",
                hasChildren: "HasEmployees"
            }
        }
    });

    $("#treeview").kendoTreeView({
        dataSource: homogeneous,
        dataTextField: "FullName"
    });

    $("#cloneNode").on("click", function(e) {
        var tree = $("#treeview").data("kendoTreeView"),
            selected = tree.select();

        if (selected.length == 0) {
            alert("Select item first!");
            return;
        }

        var dataItem = tree.dataItem(selected);

        var load = function (item) {
            var that = this,
                chain = $.Deferred().resolve();

            chain = chain.then(function () {
                return item.load();
            }).then(function () {
                if (item.hasChildren) {
                    var childrenChain = $.Deferred().resolve();

                    item.children.data().forEach(function (child) {
                        (function (child) {
                            childrenChain = childrenChain.then(function () {
                                return load(child);
                            });
                        })(child);
                    });
                    return childrenChain;
                }
            });

            return chain;
        }

        var updateIds = function (dataItem) {
          dataItem.id = kendo.guid();

            if (dataItem.items) {
                dataItem.items.forEach(function (child) {
                    updateIds(child);
                })
            }
        }

        var item = dataItem.toJSON();
            item.hasChildren = true;

            tree.append(
                item,
                null,
                function (e) {
                    var dataItem = tree.dataItem(e);

                    load.bind(tree)(tree.dataItem(e)).then(function () {
                        updateIds(dataItem);
                    });
                }
            );

        load(dataItem);
    });
});
</script>

See Also

• API Reference of the TreeView.