Custom Aggregates (React)

FlexGrid's columns have an aggregate property that allows you to show data summaries for the whole grid or for each group. If the built-in aggregates are not enough, you can calculate also aggregates with custom code. The grid below includes a 'Profit' column that shows the difference between 'Sales' and 'Expenses'.

The 'Profit' column is calculated in the formatItem event. The profit for regular data items is based on the actual data items. The profit for groups is calculated using the group's getAggregate method.

The 'Profit' column cannot be sorted because it is calculated dynamically, and does not belong to the data items.

Learn about FlexGrid | Custom Aggregates Documentation | FlexGrid API Reference

This example uses React.

import 'bootstrap.css'; import '@mescius/wijmo.styles/wijmo.css'; import ReactDOM from 'react-dom/client'; import React from 'react'; import useEvent from 'react-use-event-hook'; import { FlexGrid, FlexGridColumn } from '@mescius/wijmo.react.grid'; import { GroupRow } from '@mescius/wijmo.grid'; import { CollectionView, PropertyGroupDescription, Globalize, toggleClass } from '@mescius/wijmo'; import './app.css'; import { data } from './data'; const view = new CollectionView(data, { groupDescriptions: [ new PropertyGroupDescription('Grand Total', () => ''), 'country' ] }); function App() { const initializedGrid = useEvent((flex) => { flex.itemsSource = view; // start collapsed flex.collapseGroupsToLevel(1); // custom cell calculation flex.formatItem.addHandler((s, e) => { // cells and column footer panels only if (e.panel == s.cells) { // get row, column, and data item (or group description) let r = s.rows[e.row], c = s.columns[e.col], item = s.rows[e.row].dataItem, group = r instanceof GroupRow ? item : null, negative = false; // assume value is not negative // calculate profit if (c.binding == 'profit') { let profit = group ? group.getAggregate('Sum', 'sales') - group.getAggregate('Sum', 'expenses') : item.sales - item.expenses; e.cell.textContent = Globalize.format(profit, c.format); negative = profit < 0; } // update 'negative' class on cell toggleClass(e.cell, 'negative', negative); } }); }); return (<div className="container-fluid"> <FlexGrid initialized={initializedGrid}> <FlexGridColumn binding="id" header="ID" width={60} isReadOnly={true}/> <FlexGridColumn binding="country" header="Country"/> <FlexGridColumn binding="product" header="Product"/> <FlexGridColumn binding="sales" header="Sales" aggregate="Sum"/> <FlexGridColumn binding="expenses" header="Expenses" aggregate="Sum"/> <FlexGridColumn binding="profit" header="Profit" dataType={2} isReadOnly={true} allowSorting={false}/> </FlexGrid> </div>); } const container = document.getElementById('app'); if (container) { const root = ReactDOM.createRoot(container); root.render(<App />); }
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <title>MESCIUS Wijmo Wijmo FlexGrid Custom Aggregation</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <!-- SystemJS --> <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.40/system.src.js" integrity="sha512-G6mEj6h18+m3MvzdviSDfPle/TfH0//cXcB33AKlNR/Rha0yQsKefDZKRTkIZos97HEGq2JMV1RT5ybMoQ3WsQ==" crossorigin="anonymous"></script> <script src="systemjs.config.js"></script> <script> System.import('./src/app'); </script> </head> <body> <div id="app"></div> </body> </html>
.wj-flexgrid { max-height: 250px; margin: 10px 0; } .wj-cell.wj-frozen-row { border-bottom: none; } .negative { color: red; }
function getData() { // create some random data let countries = ['US', 'Germany', 'UK', 'Japan', 'Italy', 'Greece'], products = 'Phones,Computers,Cameras,Stereos'.split(','), data = []; for (let i = 0; i < 200; i++) { data.push({ id: i, country: countries[i % countries.length], product: products[i % products.length], sales: Math.random() * 10000, expenses: Math.random() * 5000 }); } return data; } export const data = getData();
(function (global) { System.config({ transpiler: 'plugin-babel', babelOptions: { es2015: true, react: true }, meta: { '*.css': { loader: 'css' } }, paths: { // paths serve as alias 'npm:': 'node_modules/' }, // map tells the System loader where to look for things map: { 'jszip': 'npm:jszip/dist/jszip.js', '@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': 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