Angular Drop Down Box - Single Selection

import {

  enableProdMode, ChangeDetectionStrategy, ChangeDetectorRef, Component, NgModule, ViewChild,

} from '@angular/core';

import { HttpClient, HttpClientModule } from '@angular/common/http';

import { BrowserModule } from '@angular/platform-browser';

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { lastValueFrom } from 'rxjs';

import CustomStore from 'devextreme/data/custom_store';

import { DxDataGridModule } from 'devextreme-angular';

import { DxTreeViewModule, DxTreeViewComponent, DxTreeViewTypes } from 'devextreme-angular/ui/tree-view';

import { DxDropDownBoxModule, DxDropDownBoxTypes } from 'devextreme-angular/ui/drop-down-box';

​

if (!/localhost/.test(document.location.host)) {

  enableProdMode();

}

​

let modulePrefix = '';

// @ts-ignore

if (window && window.config?.packageConfigPaths) {

  modulePrefix = '/app';

}

​

@Component({

  selector: 'demo-app',

  templateUrl: `app/app.component.html`,

  styleUrls: [`app/app.component.css`],

  changeDetection: ChangeDetectionStrategy.OnPush,

})

export class AppComponent {

  @ViewChild(DxTreeViewComponent, { static: false }) treeView: DxTreeViewComponent;

​

  treeDataSource: CustomStore;

​

  gridDataSource: CustomStore;

​

  isTreeBoxOpened = false;

​

  isGridBoxOpened = false;

​

  gridBoxValue = [3];

​

  treeBoxValue: string | string[] = '1_1';

​

  gridColumns = ['CompanyName', 'City', 'Phone'];

​

  constructor(private httpClient: HttpClient, private ref: ChangeDetectorRef) {

    this.treeDataSource = this.makeAsyncDataSource(this.httpClient, 'treeProducts.json');

    this.gridDataSource = this.makeAsyncDataSource(this.httpClient, 'customers.json');

  }

​

  makeAsyncDataSource(http: HttpClient, jsonFile: string) {

    return new CustomStore({

      loadMode: 'raw',

      key: 'ID',

      load() {

        return lastValueFrom(http.get(`data/${jsonFile}`));

      },

    });

  }

​

  syncTreeViewSelection() {

    if (!this.treeView) return;

​

    if (this.treeBoxValue) {

      this.treeView.instance.selectItem(this.treeBoxValue);

    } else {

      this.treeView.instance.unselectAll();

    }

  }

​

  treeView_itemSelectionChanged(e: DxTreeViewTypes.ItemSelectionChangedEvent) {

    this.treeBoxValue = e.component.getSelectedNodeKeys();

  }

​

  gridBox_displayExpr = ({ CompanyName, Phone }) => CompanyName && `${CompanyName} <${Phone}>`;

​

  onTreeBoxOptionChanged(e: DxDropDownBoxTypes.OptionChangedEvent) {

    if (e.name === 'value') {

      this.isTreeBoxOpened = false;

      this.ref.detectChanges();

    }

  }

​

  onGridBoxOptionChanged(e: DxDropDownBoxTypes.OptionChangedEvent) {

    if (e.name === 'value') {

      this.isGridBoxOpened = false;

      this.ref.detectChanges();

    }

  }

}

​

@NgModule({

  imports: [

    BrowserModule,

    DxTreeViewModule,

    DxDropDownBoxModule,

    HttpClientModule,

    DxDataGridModule,

  ],

  declarations: [AppComponent],

  bootstrap: [AppComponent],

})

export class AppModule { }

​

platformBrowserDynamic().bootstrapModule(AppModule);

​

:host .dx-fieldset {

  height: 500px;

}

​

// 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/

const componentNames = [

  'accordion',

  'action-sheet',

  'autocomplete',

  'bar-gauge',

  'box',

  'bullet',

  'button-group',

  'button',

  'calendar',

  'chart',

  'chat',

  'check-box',

  'circular-gauge',

  'color-box',

  'context-menu',

  'data-grid',

  'date-box',

  'date-range-box',

  'defer-rendering',

  'diagram',

  'draggable',

  'drawer',

  'drop-down-box',

  'drop-down-button',

  'file-manager',

  'file-uploader',

  'filter-builder',

  'form',

  'funnel',

  'gallery',

  'gantt',

  'html-editor',

  'linear-gauge',

  'list',

  'load-indicator',

  'load-panel',

  'lookup',

  'map',

  'menu',

  'multi-view',

  'nested',

  'number-box',

  'pagination',

  'pie-chart',

  'pivot-grid-field-chooser',

  'pivot-grid',

  'polar-chart',

  'popover',

  'popup',

  'progress-bar',

  'radio-group',

  'range-selector',

  'range-slider',

  'recurrence-editor',

  'resizable',

  'responsive-box',

  'sankey',

  'scheduler',

  'scroll-view',

  'select-box',

  'slider',

  'sortable',

  'sparkline',

  'speed-dial-action',

  'splitter',

  'switch',

  'tab-panel',

  'tabs',

  'tag-box',

  'text-area',

  'text-box',

  'tile-view',

  'toast',

  'toolbar',

  'tooltip',

  'tree-list',

  'tree-map',

  'tree-view',

  'validation-group',

  'validation-summary',

  'validator',

  'vector-map',

];

window.exports = window.exports || {};

window.config = {

  transpiler: 'ts',

  typescriptOptions: {

    module: 'system',

    emitDecoratorMetadata: true,

    experimentalDecorators: true,

  },

  meta: {

    'typescript': {

      'exports': 'ts',

    },

    'devextreme/time_zone_utils.js': {

      'esModule': true,

    },

    'devextreme/localization.js': {

      'esModule': true,

    },

    'devextreme/viz/palette.js': {

      'esModule': true,

    },

    '@angular/platform-browser-dynamic': {

      'esModule': true,

    },

    '@angular/platform-browser': {

      'esModule': true,

    },

    '@angular/core': {

      'esModule': true,

    },

    '@angular/common': {

      'esModule': true,

    },

    '@angular/common/http': {

      'esModule': true,

    },

    '@angular/animations': {

      'esModule': true,

    },

    '@angular/forms': {

      'esModule': true,

    },

    'openai': {

      'esModule': true,

    },

  },

  paths: {

    'npm:': 'https://unpkg.com/',

    'bundles:': 'bundles/',

    'externals:': 'bundles/externals/',

  },

  map: {

    'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js',

    'typescript': 'npm:typescript@4.2.4/lib/typescript.js',

    'jszip': 'npm:jszip@3.10.1/dist/jszip.min.js',

    /* @angular */

    '@angular/compiler': 'bundles:@angular/compiler.umd.js',

    '@angular/platform-browser-dynamic': 'bundles:@angular/platform-browser-dynamic.umd.js',

    '@angular/core': 'bundles:@angular/core.umd.js',

    '@angular/core/primitives/signals': 'bundles:@angular/core.primitives.signals.umd.js',

    '@angular/common': 'bundles:@angular/common.umd.js',

    '@angular/common/http': 'bundles:@angular/common-http.umd.js',

    '@angular/platform-browser': 'bundles:@angular/platform-browser.umd.js',

    '@angular/platform-browser/animations': 'bundles:@angular/platform-browser.umd.js',

    '@angular/forms': 'bundles:@angular/forms.umd.js',

    /* devextreme */

    'devextreme': 'npm:devextreme@24.2.5/cjs',

    '@devextreme/runtime': 'npm:@devextreme/runtime@3.0.12',

    'devextreme/bundles/dx.all': 'npm:devextreme@24.2.5/bundles/dx.all.js',

    'devextreme-quill': 'npm:devextreme-quill@1.7.1/dist/dx-quill.min.js',

    'devexpress-diagram': 'npm:devexpress-diagram@2.2.5',

    'devexpress-gantt': 'npm:devexpress-gantt@4.1.54',

    /* devextreme-angular umd maps */

    'devextreme-angular': 'bundles:devextreme-angular/devextreme-angular.umd.js',

    'devextreme-angular/core': 'bundles:devextreme-angular/devextreme-angular-core.umd.js',

    'devextreme-angular/http': 'bundles:devextreme-angular/devextreme-angular-http.umd.js',

    ...componentNames.reduce((acc, name) => {

      acc[`devextreme-angular/ui/${name}`] = `bundles:devextreme-angular/devextreme-angular-ui-${name}.umd.js`;

      acc[`devextreme-angular/ui/${name}/nested`] = `bundles:devextreme-angular/devextreme-angular-ui-${name}-nested.umd.js`;

      return acc;

    }, {}),

    'tslib': 'npm:tslib/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@3.4.4/build/global/luxon.min.js',

    'es6-object-assign': 'npm:es6-object-assign',

    '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/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@2.8.8/standalone.js',

    'prettier/parser-html': 'npm:prettier@2.8.8/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@3.0.12/inferno/package.json',

    'npm:rxjs@7.5.3/package.json',

    'npm:rxjs@7.5.3/operators/package.json',

    'npm:devexpress-diagram@2.2.5/package.json',

    'npm:devexpress-gantt@4.1.54/package.json',

  ],

};

System.config(window.config);

// System.import('@angular/compiler').catch(console.error.bind(console));

​

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml" lang="en">

  <head>↔</head>

​

  <body class="dx-viewport">

    <div class="demo-container">

      <demo-app>Loading...</demo-app>

    </div>

  </body>

</html>

​

[{

    "ID": 1,

    "CompanyName": "Premier Buy",

    "Address": "7601 Penn Avenue South",

    "City": "Richfield",

    "State": "Minnesota",

    "Zipcode": 55423,

    "Phone": "(612) 291-1000",

    "Fax": "(612) 291-2001",

    "Website": "http://www.nowebsitepremierbuy.dx"

}, {

    "ID": 2,

    "CompanyName": "ElectrixMax",

    "Address": "263 Shuman Blvd",

    "City": "Naperville",

    "State": "Illinois",

    "Zipcode": 60563,

    "Phone": "(630) 438-7800",

    "Fax": "(630) 438-7801",

    "Website": "http://www.nowebsiteelectrixmax.dx"

}, {

    "ID": 3,

    "CompanyName": "Video Emporium",

    "Address": "1201 Elm Street",

    "City": "Dallas",

    "State": "Texas",

    "Zipcode": 75270,

    "Phone": "(214) 854-3000",

    "Fax": "(214) 854-3001",

    "Website": "http://www.nowebsitevideoemporium.dx"

}, {

    "ID": 4,

    "CompanyName": "Screen Shop",

    "Address": "1000 Lowes Blvd",

    "City": "Mooresville",

    "State": "North Carolina",

    "Zipcode": 28117,

    "Phone": "(800) 445-6937",

    "Fax": "(800) 445-6938",

    "Website": "http://www.nowebsitescreenshop.dx"

}, {

    "ID": 5,

    "CompanyName": "Braeburn",

    "Address": "1 Infinite Loop",

    "City": "Cupertino",

    "State": "California",

    "Zipcode": 95014,

    "Phone": "(408) 996-1010",

    "Fax": "(408) 996-1012",

    "Website": "http://www.nowebsitebraeburn.dx"

}, {

    "ID": 6,

    "CompanyName": "PriceCo",

    "Address": "30 Hunter Lane",

    "City": "Camp Hill",

    "State": "Pennsylvania",

    "Zipcode": 17011,

    "Phone": "(717) 761-2633",

    "Fax": "(717) 761-2334",

    "Website": "http://www.nowebsitepriceco.dx"

}, {

    "ID": 7,

    "CompanyName": "Ultimate Gadget",

    "Address": "1557 Watson Blvd",

    "City": "Warner Robbins",

    "State": "Georgia",

    "Zipcode": 31093,

    "Phone": "(995) 623-6785",

    "Fax": "(995) 623-6786",

    "Website": "http://www.nowebsiteultimategadget.dx"

}, {

    "ID": 8,

    "CompanyName": "EZ Stop",

    "Address": "618 Michillinda Ave.",

    "City": "Arcadia",

    "State": "California",

    "Zipcode": 91007,

    "Phone": "(626) 265-8632",

    "Fax": "(626) 265-8633",

    "Website": "http://www.nowebsiteezstop.dx"

}, {

    "ID": 9,

    "CompanyName": "Clicker",

    "Address": "1100 W. Artesia Blvd.",

    "City": "Compton",

    "State": "California",

    "Zipcode": 90220,

    "Phone": "(310) 884-9000",

    "Fax": "(310) 884-9001",

    "Website": "http://www.nowebsiteclicker.dx"

}, {

    "ID": 10,

    "CompanyName": "Store of America",

    "Address": "2401 Utah Ave. South",

    "City": "Seattle",

    "State": "Washington",

    "Zipcode": 98134,

    "Phone": "(206) 447-1575",

    "Fax": "(206) 447-1576",

    "Website": "http://www.nowebsiteamerica.dx"

}, {

    "ID": 11,

    "CompanyName": "Zone Toys",

    "Address": "1945 S Cienega Boulevard",

    "City": "Los Angeles",

    "State": "California",

    "Zipcode": 90034,

    "Phone": "(310) 237-5642",

    "Fax": "(310) 237-5643",

    "Website": "http://www.nowebsitezonetoys.dx"

}, {

    "ID": 12,

    "CompanyName": "ACME",

    "Address": "2525 E El Segundo Blvd",

    "City": "El Segundo",

    "State": "California",

    "Zipcode": 90245,

    "Phone": "(310) 536-0611",

    "Fax": "(310) 536-0612",

    "Website": "http://www.nowebsiteacme.dx"

}]

[

  {

    "ID": 1,

    "name": "Stores",

    "expanded": true

  },

  {

    "ID": "1_1",

    "categoryId": 1,

    "name": "Super Mart of the West",

    "expanded": true

  },

  {

    "ID": "1_1_1",

    "categoryId": "1_1",

    "name": "Video Players"

  },

  {

    "ID": "1_1_1_1",

    "categoryId": "1_1_1",

    "name": "HD Video Player",

    "price": 220

  },

  {

    "ID": "1_1_1_2",

    "categoryId": "1_1_1",

    "name": "SuperHD Video Player",

    "price": 270

  },

  {

    "ID": "1_1_2",

    "categoryId": "1_1",

    "name": "Televisions",

    "expanded": true

  },

  {

    "ID": "1_1_2_1",

    "categoryId": "1_1_2",

    "name": "SuperLCD 42",

    "price": 1200

  },

  {

    "ID": "1_1_2_2",

    "categoryId": "1_1_2",

    "name": "SuperLED 42",

    "price": 1450

  },

  {

    "ID": "1_1_2_3",

    "categoryId": "1_1_2",

    "name": "SuperLED 50",

    "price": 1600

  },

  {

    "ID": "1_1_2_4",

    "categoryId": "1_1_2",

    "name": "SuperLCD 55",

    "price": 1750

  },

  {

    "ID": "1_1_2_5",

    "categoryId": "1_1_2",

    "name": "SuperLCD 70",

    "price": 4000

  },

  {

    "ID": "1_1_3",

    "categoryId": "1_1",

    "name": "Monitors"

  },

  {

    "ID": "1_1_3_1",

    "categoryId": "1_1_3",

    "name": "19\""

  },

  {

    "ID": "1_1_3_1_1",

    "categoryId": "1_1_3_1",

    "name": "DesktopLCD 19",

    "price": 160

  },

  {

    "ID": "1_1_4",

    "categoryId": "1_1",

    "name": "Projectors"

  },

  {

    "ID": "1_1_4_1",

    "categoryId": "1_1_4",

    "name": "Projector Plus",

    "price": 550

  },

  {

    "ID": "1_1_4_2",

    "categoryId": "1_1_4",

    "name": "Projector PlusHD",

    "price": 750

  }

]