columns.headerTemplate String|Function

The template which renders the column header content. By default, the value of the title column option is displayed in the column header cell.

If sorting is enabled, the column header content will be wrapped in an <a> element. As a result, the template must contain only inline elements.

Example - defining the column header template as a string

<div id="treelist"></div>
<script>
    $("#treelist").kendoTreeList({
        columns: [ {
            field: "lastName",
            headerTemplate: '<input type="checkbox" id="check-all" /><label for="check-all">check all</label>'
        }],
        dataSource: {
            data: [
                { id: 1, parentId: null, lastName: "Jackson" },
                { id: 2, parentId: 1, lastName: "Weber" }
            ]
        }
    });
</script>