Calculated Fields (React)

The CollectionView allows you to add calculated fields to your data sources.

This is done by setting the calculatedFields property to a value that contains the names of the calculated fields and functions used to get the field values.

The functions may be specified as regular JavaScript functions that take the current data item as argument or as string expressions with an "$" value that represents the current data item.

Calculated fields are read-only and are automatically updated their dependent fields change.

Note: To use calculated fields in IE11, you must include a proxy polyfill such as https://www.npmjs.com/package/proxy-polyfill.

This example uses React.

import 'bootstrap.css'; import '@mescius/wijmo.styles/wijmo.css'; import ReactDOM from 'react-dom/client'; import React from 'react'; import { FlexGrid, FlexGridColumn } from '@mescius/wijmo.react.grid'; import './app.css'; import { view } from './data'; function App() { return (<div className="container-fluid"> <FlexGrid alternatingRowStep={0} showMarquee={true} selectionMode="MultiRange" autoGenerateColumns={false} itemsSource={view}> {/* regular fields */} <FlexGridColumn binding="product" header="Product"/> <FlexGridColumn binding="brand" header="Brand"/> <FlexGridColumn binding="unitPrice" header="Unit Price" format="c"/> <FlexGridColumn binding="qty" header="Quantity" format="n0"/> <FlexGridColumn binding="discount" header="Discount" format="p0"/> {/* calculated fields */} <FlexGridColumn binding="fullName" header="Full Name" cssClass="calculated"/> <FlexGridColumn binding="allCaps" header="Uppercase" cssClass="calculated"/> <FlexGridColumn binding="totalPrice" header="Total Price" format="c" cssClass="calculated"/> <FlexGridColumn binding="tax" header="Tax Amount" format="c" cssClass="calculated"/> </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 CollectionView Editing</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>
.calculated { background-color: azure; }
import { CollectionView } from '@mescius/wijmo'; function getData() { return [ { product: 'Banana', brand: 'Chiquita', unitPrice: 45.95, qty: 12, discount: .08 }, { product: 'Apple', brand: 'Granny', unitPrice: 65.95, qty: 23, discount: .02 }, { product: 'Orange', brand: 'Sunkist', unitPrice: 52.95, qty: 16, discount: .04 }, { product: 'Grape', brand: 'Pinot', unitPrice: 83.95, qty: 8, discount: .0 }, { product: 'Watermelon', brand: '', unitPrice: 13.95, qty: 14, discount: .05 }, { product: 'Mango', brand: 'Ganesh', unitPrice: 38.95, qty: 19, discount: .15 }, ]; } function getCalculatedView() { return new CollectionView(getData(), { calculatedFields: { // function-based expressions fullName: ($) => [$.brand, $.product].join(' '), allCaps: ($) => $.fullName.toUpperCase(), totalPrice: ($) => ($.unitPrice * $.qty) * (1 - $.discount), tax: ($) => $.totalPrice * 0.12, // string-based expressions fullNameStr: '[$.brand, $.product].join(" ")', allCapsStr: '$.fullNameStr.toUpperCase()', totalPriceStr: '($.unitPrice * $.qty) * (1 - $.discount)', taxStr: '$.totalPrice * 0.12', } }); } export const view = getCalculatedView();
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