Cascading Lookups
Documentation
This demo shows how to populate a lookup column depending on the value of another column. For example, if you select a state, the City column allows selecting cities located only in this state. In code, this is achieved by applying a filter to the lookup data source in the lookup.dataSource function. Also, take note of the columns.setCellValue function that resets the selected city each time you choose another state, and the onEditorPreparing function that disables the City cell if the state is undefined.
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<div id="data-grid-demo">
<dx-data-grid
id="gridContainer"
keyExpr="ID"
[dataSource]="dataSource"
[showBorders]="true"
(onEditorPreparing)="onEditorPreparing($event)">
<dxo-editing
mode="row"
[allowUpdating]="true"
[allowAdding]="true">
</dxo-editing>
<dxi-column dataField="FirstName"></dxi-column>
<dxi-column dataField="LastName"></dxi-column>
<dxi-column dataField="Position"></dxi-column>
<dxi-column
dataField="StateID"
caption="State"
[setCellValue]="setStateValue">
<dxo-lookup
[dataSource]="states"
valueExpr="ID"
displayExpr="Name">
</dxo-lookup>
</dxi-column>
<dxi-column
dataField="CityID"
caption="City">
<dxo-lookup
[dataSource]="getFilteredCities"
valueExpr="ID"
displayExpr="Name">
</dxo-lookup>
</dxi-column>
</dx-data-grid>
</div>
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 2 and DevExtreme here:
// https://github.com/DevExpress/devextreme-angular/blob/master/README.md
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@19.1',
'jszip': 'npm:jszip@3.1.3/dist/jszip.min.js',
'quill': 'npm:quill@1.3.6/dist/quill.js',
'devexpress-diagram': 'npm:devexpress-diagram',
'devextreme-angular': 'npm:devextreme-angular@19.1'
},
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/19.1.5/css/dx.common.css" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.1.5/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>