Lazy-Loaded TreeGrid (Vue)

In the TreeGrid below, collapsed nodes have a single dummy child. When a node is expanded, more nodes are loaded on demand. This is a common pattern known as 'lazy-loading', and is done by utilizing the groupCollapsedChanged event.

Learn about TreeGrid | Lazy-Loaded Trees Documentation | FlexGrid API Reference

This example uses Vue.

<template> <div class="container-fluid"> <wj-flex-grid :items-source="data" headers-visibility="Column" child-items-path="children" :group-collapsed-changed="onGroupCollapsedChanged" :initialized="initialGrid"> <wj-flex-grid-column binding="name" header="Customer Name" width="*"></wj-flex-grid-column> <wj-flex-grid-column binding="id" header="ID" align="center" css-class="id-column"></wj-flex-grid-column> </wj-flex-grid> <p> The grid currently has <b id="rowCount" v-html="rowCountText"></b> rows. </p> </div> </template> <script> import "@mescius/wijmo.styles/wijmo.css"; import "bootstrap.css"; import Vue from "vue"; import * as wjcCore from '@mescius/wijmo'; import "@mescius/wijmo.vue2.grid"; import { getData, createNode } from "./data"; new Vue({ el: "#app", data: function() { return { data: getData(), rowCountText: '' } }, mounted: function() { this.grid.collapseGroupsToLevel(0); this._updateRowCount(this.grid); }, methods: { initialGrid(grid) { this.grid = grid; }, onGroupCollapsedChanged(s, e) { let row = s.rows[e.row], item = row.dataItem; // did we just expand a node with a dummy child? if (!row.isCollapsed && item.children.length == 1 && item.children[0].name == '') { // can't lazy load while updating rows if (s.rows.isUpdating) { row.isCollapsed = true; return; } // replace the dummy child with actual nodes item.children.length = 0; let cnt = Math.round(Math.random() * 5) + 1; for (let i = 0; i < cnt; i++) { let node = createNode(); item.children.push(node); } // refresh the view s.collectionView.refresh(); // collapse the new item's child items for (let i = row.index + 1; i < s.rows.length; i++) { let childRow = s.rows[i]; if (childRow.level <= row.level) { break; } childRow.isCollapsed = true; } // update row count this._updateRowCount(s); } }, _updateRowCount(grid) { this.rowCountText = wjcCore.Globalize.format(grid.rows.length, 'n0'); } } }); </script> <style> .wj-flexgrid { max-height: 300px; margin: 12px; } .wj-flexgrid .wj-cell { padding: 8px; } .wj-flexgrid .wj-group:not(.wj-state-selected):not(.wj-state-multi-selected) { background-color: white; } .id-column { font-style: italic; } document { margin-bottom: 48pt; } </style>
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <title>MESCIUS Wijmo FlexGrid Lazy Loading Tree Grid</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <!-- SystemJS --> <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.21.5/system.src.js" integrity="sha512-skZbMyvYdNoZfLmiGn5ii6KmklM82rYX2uWctBhzaXPxJgiv4XBwJnFGr5k8s+6tE1pcR1nuTKghozJHyzMcoA==" crossorigin="anonymous"></script> <script src="systemjs.config.js"></script> <script> System.import('./src/app.vue'); </script> </head> <body> <div id="app"> </div> </body> </html>
var nodeId; export function getData() { var tree = []; tree.push(createNode()); tree.push(createNode()); return tree; } export function createNode(dummy) { var first = 'Al,Bob,Cal,Dan,Ed,Fred,Greg,Hal,Ian,Jack,Karl,Lou,Moe,Nate,Oleg,Paul,Quincy,Rod,Sue,Uwe,Vic,Walt,Xiu,Yuri,Zack'.split(','), last = 'Adams,Baum,Cole,Dell,Evans,Fell,Green,Hill,Isman,Jones,Krup,Lee,Monk,Nye,Opus,Pitt,Quaid,Riems,Stark,Trell,Unger,Voss,Wang,Xie,Zalm'.split(','), name = dummy ? '' : getOneOf(first) + ' ' + getOneOf(last), children = []; if (!dummy) { children.push(createNode(true)); } if (nodeId == null) nodeId = 0; return { id: nodeId++, name: name, children: children }; } function getOneOf(arr) { return arr[Math.floor(Math.random() * arr.length)]; }
(function (global) { System.config({ transpiler: 'plugin-babel', babelOptions: { es2015: true }, meta: { '*.css': { loader: 'css' }, '*.vue': { loader: 'vue-loader' } //'*.vue': { loader: 'systemjs-plugin-vue' } }, paths: { // paths serve as alias 'npm:': 'node_modules/' }, // map tells the System loader where to look for things map: { '@mescius/wijmo': 'npm:@mescius/wijmo/index.js', '@mescius/wijmo.input': 'npm:@mescius/wijmo.input/index.js', '@mescius/wijmo.styles': 'npm:@mescius/wijmo.styles', '@mescius/wijmo.cultures': 'npm:@mescius/wijmo.cultures', '@mescius/wijmo.chart': 'npm:@mescius/wijmo.chart/index.js', '@mescius/wijmo.chart.analytics': 'npm:@mescius/wijmo.chart.analytics/index.js', '@mescius/wijmo.chart.animation': 'npm:@mescius/wijmo.chart.animation/index.js', '@mescius/wijmo.chart.annotation': 'npm:@mescius/wijmo.chart.annotation/index.js', '@mescius/wijmo.chart.finance': 'npm:@mescius/wijmo.chart.finance/index.js', '@mescius/wijmo.chart.finance.analytics': 'npm:@mescius/wijmo.chart.finance.analytics/index.js', '@mescius/wijmo.chart.hierarchical': 'npm:@mescius/wijmo.chart.hierarchical/index.js', '@mescius/wijmo.chart.interaction': 'npm:@mescius/wijmo.chart.interaction/index.js', '@mescius/wijmo.chart.radar': 'npm:@mescius/wijmo.chart.radar/index.js', '@mescius/wijmo.chart.render': 'npm:@mescius/wijmo.chart.render/index.js', '@mescius/wijmo.chart.webgl': 'npm:@mescius/wijmo.chart.webgl/index.js', '@mescius/wijmo.chart.map': 'npm:@mescius/wijmo.chart.map/index.js', '@mescius/wijmo.gauge': 'npm:@mescius/wijmo.gauge/index.js', '@mescius/wijmo.grid': 'npm:@mescius/wijmo.grid/index.js', '@mescius/wijmo.grid.detail': 'npm:@mescius/wijmo.grid.detail/index.js', '@mescius/wijmo.grid.filter': 'npm:@mescius/wijmo.grid.filter/index.js', '@mescius/wijmo.grid.search': 'npm:@mescius/wijmo.grid.search/index.js', '@mescius/wijmo.grid.grouppanel': 'npm:@mescius/wijmo.grid.grouppanel/index.js', '@mescius/wijmo.grid.multirow': 'npm:@mescius/wijmo.grid.multirow/index.js', '@mescius/wijmo.grid.transposed': 'npm:@mescius/wijmo.grid.transposed/index.js', '@mescius/wijmo.grid.transposedmultirow': 'npm:@mescius/wijmo.grid.transposedmultirow/index.js', '@mescius/wijmo.grid.pdf': 'npm:@mescius/wijmo.grid.pdf/index.js', '@mescius/wijmo.grid.sheet': 'npm:@mescius/wijmo.grid.sheet/index.js', '@mescius/wijmo.grid.xlsx': 'npm:@mescius/wijmo.grid.xlsx/index.js', '@mescius/wijmo.grid.selector': 'npm:@mescius/wijmo.grid.selector/index.js', '@mescius/wijmo.grid.cellmaker': 'npm:@mescius/wijmo.grid.cellmaker/index.js', '@mescius/wijmo.nav': 'npm:@mescius/wijmo.nav/index.js', '@mescius/wijmo.odata': 'npm:@mescius/wijmo.odata/index.js', '@mescius/wijmo.olap': 'npm:@mescius/wijmo.olap/index.js', '@mescius/wijmo.rest': 'npm:@mescius/wijmo.rest/index.js', '@mescius/wijmo.pdf': 'npm:@mescius/wijmo.pdf/index.js', '@mescius/wijmo.pdf.security': 'npm:@mescius/wijmo.pdf.security/index.js', '@mescius/wijmo.viewer': 'npm:@mescius/wijmo.viewer/index.js', '@mescius/wijmo.xlsx': 'npm:@mescius/wijmo.xlsx/index.js', '@mescius/wijmo.undo': 'npm:@mescius/wijmo.undo/index.js', '@mescius/wijmo.interop.grid': 'npm:@mescius/wijmo.interop.grid/index.js', '@mescius/wijmo.touch': 'npm:@mescius/wijmo.touch/index.js', '@mescius/wijmo.cloud': 'npm:@mescius/wijmo.cloud/index.js', '@mescius/wijmo.barcode': 'npm:@mescius/wijmo.barcode/index.js', '@mescius/wijmo.barcode.common': 'npm:@mescius/wijmo.barcode.common/index.js', '@mescius/wijmo.barcode.composite': 'npm:@mescius/wijmo.barcode.composite/index.js', '@mescius/wijmo.barcode.specialized': 'npm:@mescius/wijmo.barcode.specialized/index.js', "@mescius/wijmo.vue2.chart.analytics": "npm:@mescius/wijmo.vue2.chart.analytics/index.js", "@mescius/wijmo.vue2.chart.animation": "npm:@mescius/wijmo.vue2.chart.animation/index.js", "@mescius/wijmo.vue2.chart.annotation": "npm:@mescius/wijmo.vue2.chart.annotation/index.js", "@mescius/wijmo.vue2.chart.finance.analytics": "npm:@mescius/wijmo.vue2.chart.finance.analytics/index.js", "@mescius/wijmo.vue2.chart.finance": "npm:@mescius/wijmo.vue2.chart.finance/index.js", "@mescius/wijmo.vue2.chart.hierarchical": "npm:@mescius/wijmo.vue2.chart.hierarchical/index.js", "@mescius/wijmo.vue2.chart.interaction": "npm:@mescius/wijmo.vue2.chart.interaction/index.js", "@mescius/wijmo.vue2.chart.radar": "npm:@mescius/wijmo.vue2.chart.radar/index.js", '@mescius/wijmo.vue2.chart.map': 'npm:@mescius/wijmo.vue2.chart.map/index.js', "@mescius/wijmo.vue2.chart": "npm:@mescius/wijmo.vue2.chart/index.js", "@mescius/wijmo.vue2.core": "npm:@mescius/wijmo.vue2.core/index.js", "@mescius/wijmo.vue2.gauge": "npm:@mescius/wijmo.vue2.gauge/index.js", "@mescius/wijmo.vue2.grid.detail": "npm:@mescius/wijmo.vue2.grid.detail/index.js", "@mescius/wijmo.vue2.grid.filter": "npm:@mescius/wijmo.vue2.grid.filter/index.js", "@mescius/wijmo.vue2.grid.grouppanel": "npm:@mescius/wijmo.vue2.grid.grouppanel/index.js", '@mescius/wijmo.vue2.grid.search': 'npm:@mescius/wijmo.vue2.grid.search/index.js', "@mescius/wijmo.vue2.grid.multirow": "npm:@mescius/wijmo.vue2.grid.multirow/index.js", "@mescius/wijmo.vue2.grid.sheet": "npm:@mescius/wijmo.vue2.grid.sheet/index.js", '@mescius/wijmo.vue2.grid.transposed': 'npm:@mescius/wijmo.vue2.grid.transposed/index.js', '@mescius/wijmo.vue2.grid.transposedmultirow': 'npm:@mescius/wijmo.vue2.grid.transposedmultirow/index.js', "@mescius/wijmo.vue2.grid": "npm:@mescius/wijmo.vue2.grid/index.js", "@mescius/wijmo.vue2.input": "npm:@mescius/wijmo.vue2.input/index.js", "@mescius/wijmo.vue2.olap": "npm:@mescius/wijmo.vue2.olap/index.js", "@mescius/wijmo.vue2.viewer": "npm:@mescius/wijmo.vue2.viewer/index.js", "@mescius/wijmo.vue2.nav": "npm:@mescius/wijmo.vue2.nav/index.js", "@mescius/wijmo.vue2.base": "npm:@mescius/wijmo.vue2.base/index.js", '@mescius/wijmo.vue2.barcode.common': 'npm:@mescius/wijmo.vue2.barcode.common/index.js', '@mescius/wijmo.vue2.barcode.composite': 'npm:@mescius/wijmo.vue2.barcode.composite/index.js', '@mescius/wijmo.vue2.barcode.specialized': 'npm:@mescius/wijmo.vue2.barcode.specialized/index.js', 'bootstrap.css': 'npm:bootstrap/dist/css/bootstrap.min.css', 'jszip': 'npm:jszip/dist/jszip.js', 'css': 'npm:systemjs-plugin-css/css.js', 'vue': 'npm:vue/dist/vue.min.js', 'vue-loader': 'npm:systemjs-vue-browser/index.js', //'systemjs-plugin-vue': 'npm:systemjs-plugin-vue/index.js', 'plugin-babel': 'npm:systemjs-plugin-babel/plugin-babel.js', 'systemjs-babel-build': 'npm:systemjs-plugin-babel/systemjs-babel-browser.js' }, // packages tells the System loader how to load when no filename and/or no extension packages: { src: { defaultExtension: 'js' }, rxjs: { defaultExtension: 'js' }, "node_modules": { defaultExtension: 'js' }, wijmo: { defaultExtension: 'js', } } }); })(this);