Create a User-Defined Item

A user can select existing values and add new values to the SelectBox. To enable this feature, assign true to the acceptCustomValue option. Note that you should implement the onCustomItemCreating handler to create a new data source entry.

jQuery
HTML
JavaScript
<div id="selectBoxContainer"></div>
var selectBoxData = new DevExpress.data.DataSource({
    store: [
        { id: 1, firstName: "Andrew" },
        { id: 2, firstName: "Nancy" },
        { id: 3, firstName: "Steven" }
    ]
});

$(function() {
    $("#selectBoxContainer").dxSelectBox({
        dataSource: selectBoxData,
        valueExpr: 'id',
        displayExpr: 'firstName',
        acceptCustomValue: true,
        onCustomItemCreating: function(e) {
            // Generates a new 'id'
            var nextId = Math.max.apply(Math, selectBoxData.items().map(function(c) { return c.id; })) + 1;
            // Creates a new entry
            e.customItem = { id: nextId, firstName: e.text };
            // Adds the entry to the data source
            selectBoxData.store().insert(e.customItem);
            // Reloads the data source
            selectBoxData.reload();
        }
    });
});
Angular
TypeScript
HTML
import DataSource from 'devextreme/data/data_source';
import { DxSelectBoxModule } from 'devextreme-angular';
// ...
export class AppComponent {
    selectBoxData = new DataSource({
        store: [
            { id: 1, firstName: "Andrew" },
            { id: 2, firstName: "Nancy" },
            { id: 3, firstName: "Steven" }
        ]
    });
    onCustomItemCreating (e) {
        // Generates a new 'id'
        var nextId = Math.max.apply(Math, this.selectBoxData.items().map(function(c) { return c.id; })) + 1;
        // Creates a new entry
        e.customItem = { id: nextId, firstName: e.text };
        // Adds the entry to the data source
        this.selectBoxData.store().insert(e.customItem);
        // Reloads the data source
        this.selectBoxData.reload();
    }
}
@NgModule({
     imports: [
         // ...
         DxSelectBoxModule
     ],
     // ...
 })
<dx-select-box
    [dataSource]="selectBoxData"
    valueExpr="id"
    displayExpr="firstName"
    [acceptCustomValue]="true"
    (onCustomItemCreating)="onCustomItemCreating($event)">
</dx-select-box>

View Demo

See Also