Cascading Lookups

import { NgModule, Component, enableProdMode } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { DxDataGridModule } from 'devextreme-angular'; 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(rowData: any, value: any): void { rowData.CityID = null; (<any>this).defaultSetCellValue(rowData, value); } } @NgModule({ imports: [ BrowserModule, 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; } let 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 }]; let states: State[] = [{ "ID": 1, "Name": "Alabama" }, { "ID": 2, "Name": "Alaska" }, { "ID": 3, "Name": "Arizona" }, { "ID": 4, "Name": "Arkansas" }, { "ID": 5, "Name": "California" }]; let 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/ System.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@8.0.0/lib/plugin.js', 'typescript': 'npm:typescript@3.5.3/lib/typescript.js', '@angular': 'npm:@angular', 'tslib': 'npm:tslib@2.0.3/tslib.js', 'rxjs': 'npm:rxjs@6.3.3', 'rrule': 'npm:rrule@2.6.6/dist/es5/rrule.js', 'luxon': 'npm:luxon@1.25.0/build/global/luxon.min.js', 'es6-object-assign': 'npm:es6-object-assign@1.1.0', 'devextreme': 'npm:devextreme@20.2.4', 'jszip': 'npm:jszip@3.5.0/dist/jszip.min.js', 'devextreme-quill': 'npm:devextreme-quill@0.9.7/dist/dx-quill.min.js', 'devexpress-diagram': 'npm:devexpress-diagram@2.0.5', 'devexpress-gantt': 'npm:devexpress-gantt@2.0.8', 'devextreme-angular': 'npm:devextreme-angular@20.2.4', 'preact': 'npm:preact@10.5.7/dist/preact.js', 'preact/hooks': 'npm:preact@10.5.7/hooks/dist/hooks.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' } }, packageConfigPaths: [ "npm:@angular/*/package.json", "npm:@angular/common/*/package.json", "npm:rxjs/package.json", "npm:rxjs/operators/package.json", "npm:devextreme-angular/*/package.json", "npm:devextreme-angular/ui/*/package.json", "npm:devextreme-angular/package.json", "npm:devexpress-diagram/package.json", "npm:devexpress-gantt/package.json", ] });

<!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/20.2.4/css/dx.common.css" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/20.2.4/css/dx.light.css" /> <script src="https://unpkg.com/core-js@2.4.1/client/shim.min.js"></script> <script src="https://unpkg.com/zone.js@0.10.2/dist/zone.js"></script> <script src="https://unpkg.com/reflect-metadata@0.1.3/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>