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Drop Down Box

Single Selection

The DropDownBox widget is an editor that consists of a text field and drop-down content. In this demo, the content is the TreeView and the DataGrid widgets in the single selection mode.

The following instructions show how to synchronize the DropDownBox widget with any other embedded DevExtreme widget:

  1. Specify data sources
    The DropDownBox's and embedded widget's data sources can be the same or different. If they are different, the widget's key field should be present in the DropDownBox's data source.

  2. Specify which data field provides the DropDownBox's values and the embedded widget's keys
    Assign the field's name to the DropDownBox's valueExpr option and to the key option of the embedded widget's store.

  3. Synchronize the DropDownBox's value and the embedded widget's selection
    Bind the DropDownBox's value and the widget's selectedRowKeys/selectedItemKeys option to the same variable.

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<div class="dx-fieldset"> <div class="dx-field"> <div class="dx-field-label">DropDownBox with embedded TreeView</div> <div class="dx-field-value"> <dx-drop-down-box [(value)]="treeBoxValue" valueExpr="ID" displayExpr="name" placeholder="Select a value..." [showClearButton]="true" [dataSource]="treeDataSource" (onValueChanged)="syncTreeViewSelection($event)" > <div *dxTemplate="let data of 'content'"> <dx-tree-view [dataSource]="treeDataSource" dataStructure="plain" keyExpr="ID" parentIdExpr="categoryId" selectionMode="single" displayExpr="name" [selectByClick]="true" (onContentReady)="$event.component.selectItem(treeBoxValue)" (onItemSelectionChanged)="treeView_itemSelectionChanged($event)" > </dx-tree-view> </div> </dx-drop-down-box> </div> </div> <div class="dx-field"> <div class="dx-field-label">DropDownBox with embedded DataGrid</div> <div class="dx-field-value"> <dx-drop-down-box [(value)]="gridBoxValue" valueExpr="ID" [deferRendering]="false" [displayExpr]="gridBox_displayExpr" placeholder="Select a value..." [showClearButton]="true" [dataSource]="gridDataSource" > <div *dxTemplate="let data of 'content'"> <dx-data-grid [dataSource]="gridDataSource" [columns]="['CompanyName', 'City', 'Phone']" [selection]="{ mode: 'single' }" [hoverStateEnabled]="true" [paging]="{ enabled: true, pageSize: 10 }" [filterRow]="{ visible: true }" [scrolling]="{ mode: 'infinite' }" [(selectedRowKeys)]="gridBoxValue" height="100%" > </dx-data-grid> </div> </dx-drop-down-box> </div> </div> </div>
import { NgModule, Component, ViewChild, enableProdMode } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { HttpClient, HttpClientModule } from '@angular/common/http'; import { DxDropDownBoxModule, DxTreeViewModule, DxDataGridModule, DxTreeViewComponent } from 'devextreme-angular'; import CustomStore from 'devextreme/data/custom_store'; if(!/localhost/.test(document.location.host)) { enableProdMode(); } @Component({ selector: 'demo-app', templateUrl: 'app/app.component.html', styleUrls: ['app/app.component.css'] }) export class AppComponent { @ViewChild(DxTreeViewComponent, { static: false }) treeView; treeDataSource: any; treeBoxValue: string; gridDataSource: any; gridBoxValue: number[] = [3]; constructor(private httpClient: HttpClient) { this.treeDataSource = this.makeAsyncDataSource(this.httpClient, "treeProducts.json"); this.gridDataSource = this.makeAsyncDataSource(this.httpClient, "customers.json"); this.treeBoxValue = "1_1"; } makeAsyncDataSource(http, jsonFile){ return new CustomStore({ loadMode: "raw", key: "ID", load: function() { return http.get('../../../../data/' + jsonFile) .toPromise(); } }); }; syncTreeViewSelection() { if (!this.treeView) return; if (!this.treeBoxValue) { this.treeView.instance.unselectAll(); } else { this.treeView.instance.selectItem(this.treeBoxValue); } } getSelectedItemsKeys(items) { var result = [], that = this; items.forEach(function(item) { if(item.selected) { result.push(item.key); } if(item.items.length) { result = result.concat(that.getSelectedItemsKeys(item.items)); } }); return result; } treeView_itemSelectionChanged(e){ const nodes = e.component.getNodes(); this.treeBoxValue = this.getSelectedItemsKeys(nodes).join(""); } gridBox_displayExpr(item){ return item && item.CompanyName + " <" + item.Phone + ">"; } } @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/ System.config({ transpiler: 'ts', typescriptOptions: { module: "commonjs", emitDecoratorMetadata: true, experimentalDecorators: true }, meta: { 'typescript': { "exports": "ts" } }, paths: { 'npm:': 'https://unpkg.com/' }, map: { 'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js', 'typescript': 'npm:typescript@3.4.5/lib/typescript.js', '@angular/core': 'npm:@angular/core@8.0.0/bundles/core.umd.js', '@angular/common': 'npm:@angular/common@8.0.0/bundles/common.umd.js', '@angular/compiler': 'npm:@angular/compiler@8.0.0/bundles/compiler.umd.js', '@angular/platform-browser': 'npm:@angular/platform-browser@8.0.0/bundles/platform-browser.umd.js', '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic@8.0.0/bundles/platform-browser-dynamic.umd.js', '@angular/router': 'npm:@angular/router@8.0.0/bundles/router.umd.js', '@angular/forms': 'npm:@angular/forms@8.0.0/bundles/forms.umd.js', '@angular/common/http': 'npm:@angular/common@8.0.0/bundles/common-http.umd.js', 'tslib': 'npm:tslib/tslib.js', 'rxjs': 'npm:rxjs@6.3.3', 'rxjs/operators': 'npm:rxjs@6.3.3/operators', 'devextreme': 'npm:devextreme@19.2', 'jszip': 'npm:jszip@3.1.3/dist/jszip.min.js', 'quill': 'npm:quill@1.3.7/dist/quill.js', 'devexpress-diagram': 'npm:devexpress-diagram', 'devexpress-gantt': 'npm:devexpress-gantt', 'devextreme-angular': 'npm:devextreme-angular@19.2' }, packages: { 'app': { main: './app.component.ts', defaultExtension: 'ts' }, 'devextreme': { defaultExtension: 'js' }, 'rxjs': { main: 'index.js', defaultExtension: 'js' }, 'rxjs/operators': { main: 'index.js', defaultExtension: 'js' }, 'devextreme-angular': { main: 'index.js', defaultExtension: 'js' } } });
<!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/19.2.4/css/dx.common.css"/> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.2.4/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@0.6.25/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>