Cascading Lookups

import { NgModule, Component, enableProdMode } from '@angular/core'; import { BrowserModule, BrowserTransferStateModule } from '@angular/platform-browser'; import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { DxDataGridModule } from 'devextreme-angular'; import { Column } from 'devextreme/ui/data_grid'; import { Service, Employee, State, City, } from './app.service'; if (!/localhost/.test(document.location.host)) { enableProdMode(); } @Component({ selector: 'demo-app', templateUrl: 'app/app.component.html', providers: [Service], }) export class AppComponent { dataSource: Employee[]; states: State[]; cities: City[]; constructor(private service: Service) { this.dataSource = service.getEmployees(); this.states = service.getStates(); this.cities = service.getCities(); this.getFilteredCities = this.getFilteredCities.bind(this); } getFilteredCities(options) { return { store: this.cities, filter: options.data ? ['StateID', '=', options.data.StateID] : null, }; } onEditorPreparing(e) { if (e.parentType === 'dataRow' && e.dataField === 'CityID') { e.editorOptions.disabled = (typeof e.row.data.StateID !== 'number'); } } setStateValue(this: Column, newData: Employee, value: number, currentRowData: Employee) { newData.CityID = null; this.defaultSetCellValue(newData, value, currentRowData); } } @NgModule({ imports: [ BrowserModule, BrowserTransferStateModule, DxDataGridModule, ], declarations: [AppComponent], bootstrap: [AppComponent], }) export class AppModule { } platformBrowserDynamic().bootstrapModule(AppModule);

import { Injectable } from '@angular/core'; export class Employee { ID: number; FirstName: string; LastName: string; Prefix: string; Position: string; StateID: number; CityID: number; } export class State { ID: number; Name: string; } export class City { ID: number; Name: string; StateID: number; } const employees: Employee[] = [{ ID: 1, FirstName: 'John', LastName: 'Heart', Prefix: 'Mr.', Position: 'CTO', StateID: 5, CityID: 17, }, { ID: 2, FirstName: 'Olivia', LastName: 'Peyton', Prefix: 'Mrs.', Position: 'HR Manager', StateID: 5, CityID: 17, }, { ID: 3, FirstName: 'Robert', LastName: 'Reagan', Prefix: 'Mr.', Position: 'IT Manager', StateID: 4, CityID: 14, }, { ID: 4, FirstName: 'Greta', LastName: 'Sims', Prefix: 'Ms.', Position: 'Shipping Manager', StateID: 3, CityID: 8, }, { ID: 5, FirstName: 'Brett', LastName: 'Wade', Prefix: 'Mr.', Position: 'Shipping Manager', StateID: 3, CityID: 9, }, { ID: 6, FirstName: 'Sandra', LastName: 'Johnson', Prefix: 'Mrs.', Position: 'Network Admin', StateID: 2, CityID: 6, }, { ID: 7, FirstName: 'Kevin', LastName: 'Carter', Prefix: 'Mr.', Position: 'Network Admin', StateID: 1, CityID: 3, }, { ID: 8, FirstName: 'Cynthia', LastName: 'Stanwick', Prefix: 'Ms.', Position: 'Sales Assistant', StateID: 1, CityID: 3, }, { ID: 9, FirstName: 'Kent', LastName: 'Samuelson', Prefix: 'Dr.', Position: 'Sales Assistant', StateID: 1, CityID: 2, }, { ID: 10, FirstName: 'Taylor', LastName: 'Riley', Prefix: 'Mr.', Position: 'Support Assistant', StateID: 5, CityID: 17, }, { ID: 11, FirstName: 'Sam', LastName: 'Hill', Prefix: 'Mr.', Position: 'Sales Assistant', StateID: 2, CityID: 5, }, { ID: 12, FirstName: 'Kelly', LastName: 'Rodriguez', Prefix: 'Ms.', Position: 'Sales Assistant', StateID: 5, CityID: 17, }, { ID: 13, FirstName: 'Natalie', LastName: 'Maguirre', Prefix: 'Mrs.', Position: 'Sales Assistant', StateID: 4, CityID: 14, }, { ID: 14, FirstName: 'Walter', LastName: 'Hobbs', Prefix: 'Mr.', Position: 'Support Assistant', StateID: 2, CityID: 5, }]; const states: State[] = [{ ID: 1, Name: 'Alabama', }, { ID: 2, Name: 'Alaska', }, { ID: 3, Name: 'Arizona', }, { ID: 4, Name: 'Arkansas', }, { ID: 5, Name: 'California', }]; const cities: City[] = [{ ID: 1, Name: 'Tuscaloosa', StateID: 1, }, { ID: 2, Name: 'Hoover', StateID: 1, }, { ID: 3, Name: 'Dothan', StateID: 1, }, { ID: 4, Name: 'Decatur', StateID: 1, }, { ID: 5, Name: 'Anchorage', StateID: 2, }, { ID: 6, Name: 'Fairbanks', StateID: 2, }, { ID: 7, Name: 'Juneau', StateID: 2, }, { ID: 8, Name: 'Avondale', StateID: 3, }, { ID: 9, Name: 'Buckeye', StateID: 3, }, { ID: 10, Name: 'Carefree', StateID: 3, }, { ID: 11, Name: 'Springdale', StateID: 4, }, { ID: 12, Name: 'Rogers', StateID: 4, }, { ID: 13, Name: 'Sherwood', StateID: 4, }, { ID: 14, Name: 'Jacksonville', StateID: 4, }, { ID: 15, Name: 'Cabot', StateID: 4, }, { ID: 16, Name: 'Adelanto', StateID: 5, }, { ID: 17, Name: 'Glendale', StateID: 5, }, { ID: 18, Name: 'Moorpark', StateID: 5, }, { ID: 19, Name: 'Needles', StateID: 5, }, { ID: 20, Name: 'Ontario', StateID: 5, }]; @Injectable() export class Service { getEmployees() { return employees; } getStates() { return states; } getCities() { return cities; } }

// In real applications, you should not transpile code in the browser. // You can see how to create your own application with Angular and DevExtreme here: // https://js.devexpress.com/Documentation/Guide/Angular_Components/Getting_Started/Create_a_DevExtreme_Application/ window.config = { transpiler: 'ts', typescriptOptions: { module: 'system', emitDecoratorMetadata: true, experimentalDecorators: true, }, meta: { 'typescript': { 'exports': 'ts', }, 'devextreme/localization.js': { 'esModule': true, }, }, paths: { 'npm:': 'https://unpkg.com/', }, map: { 'ts': 'npm:plugin-typescript@4.2.4/lib/plugin.js', 'typescript': 'npm:typescript@4.2.4/lib/typescript.js', '@angular/core': 'npm:@angular/core@12.2.17', '@angular/platform-browser': 'npm:@angular/platform-browser@12.2.17', '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic@12.2.17', '@angular/forms': 'npm:@angular/forms@12.2.17', '@angular/common': 'npm:@angular/common@12.2.17', '@angular/compiler': 'npm:@angular/compiler@12.2.17', 'tslib': 'npm:tslib@2.3.1/tslib.js', 'rxjs': 'npm:rxjs@7.5.3/dist/bundles/rxjs.umd.js', 'rxjs/operators': 'npm:rxjs@7.5.3/dist/cjs/operators/index.js', 'rrule': 'npm:rrule@2.6.4/dist/es5/rrule.js', 'luxon': 'npm:luxon@1.28.1/build/global/luxon.min.js', 'es6-object-assign': 'npm:es6-object-assign@1.1.0', 'devextreme': 'npm:devextreme@23.1.5/cjs', 'devextreme/bundles/dx.all': 'npm:devextreme@23.1.5/bundles/dx.all.js', 'jszip': 'npm:jszip@3.7.1/dist/jszip.min.js', 'devextreme-quill': 'npm:devextreme-quill@1.6.2/dist/dx-quill.min.js', 'devexpress-diagram': 'npm:devexpress-diagram@2.2.1', 'devexpress-gantt': 'npm:devexpress-gantt@4.1.48', 'devextreme-angular': 'npm:devextreme-angular@23.1.5', '@devextreme/runtime': 'npm:@devextreme/runtime@3.0.11', 'inferno': 'npm:inferno@7.4.11/dist/inferno.min.js', 'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js', 'inferno-create-element': 'npm:inferno-create-element@7.4.11/dist/inferno-create-element.min.js', 'inferno-dom': 'npm:inferno-dom/dist/inferno-dom.min.js', 'inferno-hydrate': 'npm:inferno-hydrate@7.4.11/dist/inferno-hydrate.min.js', 'inferno-clone-vnode': 'npm:inferno-clone-vnode/dist/inferno-clone-vnode.min.js', 'inferno-create-class': 'npm:inferno-create-class/dist/inferno-create-class.min.js', 'inferno-extras': 'npm:inferno-extras/dist/inferno-extras.min.js', // Prettier 'prettier/standalone': 'npm:prettier@2.8.4/standalone.js', 'prettier/parser-html': 'npm:prettier@2.8.4/parser-html.js', }, packages: { 'app': { main: './app.component.ts', defaultExtension: 'ts', }, 'devextreme': { defaultExtension: 'js', }, 'devextreme/events/utils': { main: 'index', }, 'devextreme/events': { main: 'index', }, 'es6-object-assign': { main: './index.js', defaultExtension: 'js', }, 'rxjs': { defaultExtension: 'js', }, 'rxjs/operators': { defaultExtension: 'js', }, }, packageConfigPaths: [ 'npm:@devextreme/*/package.json', 'npm:@devextreme/runtime@3.0.11/inferno/package.json', 'npm:@angular/*/package.json', 'npm:@angular/common@12.2.17/*/package.json', 'npm:rxjs@7.5.3/package.json', 'npm:rxjs@7.5.3/operators/package.json', 'npm:devextreme-angular@23.1.5/*/package.json', 'npm:devextreme-angular@23.1.5/ui/*/package.json', 'npm:devextreme-angular@23.1.5/package.json', 'npm:devexpress-diagram@2.2.1/package.json', 'npm:devexpress-gantt@4.1.48/package.json', ], }; System.config(window.config);

<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>DevExtreme Demo</title> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/23.1.5/css/dx.light.css" /> <script src="https://unpkg.com/core-js@2.6.12/client/shim.min.js"></script> <script src="https://unpkg.com/zone.js@0.12.0/dist/zone.js"></script> <script src="https://unpkg.com/reflect-metadata@0.1.13/Reflect.js"></script> <script src="https://unpkg.com/systemjs@0.21.3/dist/system.js"></script> <script src="config.js"></script> <script> System.import("app").catch(console.error.bind(console)); </script> </head> <body class="dx-viewport"> <div class="demo-container"> <demo-app>Loading...</demo-app> </div> </body> </html>