Angular Lookup - Configure Search Parameters

NOTE
Searching works when inputting a plain data structure only. However, if you need the searching capability and hierarchical data, transform the plain data using the DataSource's group property.

The Lookup UI component allows a user to search through its items. Moreover, the UI component offers suggestions while the user types a value into the search box. Usually, the data field that provides suggestions is the same data field that is searched for the typed value. If there are two different fields, assign the field providing suggestions to the valueExpr property and the field to be searched to the searchExpr property. Assign an array of field names to the searchExpr property if you need to search several fields.

jQuery
JavaScript
const lookupData = [
    { country: "Afghanistan", capital: "Kabul" },
    { country: "Albania", capital: "Tirana" },
    // ...
];

$(function() {
    $("#lookupContainer").dxLookup({
        dataSource: lookupData,
        valueExpr: 'country',
        displayExpr: 'country',
        searchExpr: 'capital',
        placeholder: 'Select country'
    });
});
Angular
HTML
TypeScript
<dx-lookup
    [dataSource]="lookupDataSource"
    valueExpr="country"
    displayExpr="country"
    searchExpr="capital"
    placeholder="Select country">
</dx-lookup>
import { DxLookupModule } from "devextreme-angular";
// ...
export class AppComponent {
    lookupDataSource = [
        { country: "Afghanistan", capital: "Kabul" },
        { country: "Albania", capital: "Tirana" },
        // ...
    ];
}
@NgModule({
    imports: [
        // ...
        DxLookupModule
    ],
    // ...
})
Vue
<template>
    <DxLookup
        :data-source="lookupData"
        value-expr="country"
        display-expr="country"
        search-expr="capital"
        placeholder="Select country"
    />
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxLookup } from 'devextreme-vue/lookup';

export default {
    components: {
        DxLookup
    },
    data() {
        return {
            lookupData: [
                { country: 'Afghanistan', capital: 'Kabul' },
                { country: 'Albania', capital: 'Tirana' },
                // ...
            ]
        };
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { Lookup } from 'devextreme-react/lookup';

const lookupData = [
    { country: 'Afghanistan', capital: 'Kabul' },
    { country: 'Albania', capital: 'Tirana' },
    // ...
];

class App extends React.Component {
    render() {
        return (
            <Lookup
                dataSource={lookupData}
                valueExpr="country"
                displayExpr="country"
                searchExpr="capital"
                placeholder="Select country"
            />
        );
    }
}

export default App;

The Lookup UI component can provide suggestions in two different modes: 'contains' (by default) and 'startswith'. You can use the searchMode property to change the mode. You can also use the searchPlaceholder property to specify a placeholder for an empty search box.

jQuery
JavaScript
const lookupData = [
    { country: "Afghanistan", capital: "Kabul" },
    { country: "Albania", capital: "Tirana" },
    // ...
];

$(function() {
    $("#lookupContainer").dxLookup({
        dataSource: lookupData,
        valueExpr: 'country',
        displayExpr: 'country',
        searchMode: 'startswith',
        searchPlaceholder: 'Type country name'
    });
});
Angular
HTML
TypeScript
<dx-lookup
    [dataSource]="lookupDataSource"
    valueExpr="country"
    displayExpr="country"
    searchMode="startswith"
    searchPlaceholder="Type country name">
</dx-lookup>
import { DxLookupModule } from "devextreme-angular";
// ...
export class AppComponent {
    lookupDataSource = [
        { country: "Afghanistan", capital: "Kabul" },
        { country: "Albania", capital: "Tirana" },
        // ...
    ];
}
@NgModule({
    imports: [
        // ...
        DxLookupModule
    ],
    // ...
})
Vue
<template>
    <DxLookup
        :data-source="lookupData"
        value-expr="country"
        display-expr="country"
        search-mode="startswith"
        search-placeholder="Type country name"
    />
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxLookup } from 'devextreme-vue/lookup';

export default {
    components: {
        DxLookup
    },
    data() {
        return {
            lookupData: [
                { country: 'Afghanistan', capital: 'Kabul' },
                { country: 'Albania', capital: 'Tirana' },
                // ...
            ]
        };
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { Lookup } from 'devextreme-react/lookup';

const lookupData = [
    { country: 'Afghanistan', capital: 'Kabul' },
    { country: 'Albania', capital: 'Tirana' },
    // ...
];

class App extends React.Component {
    render() {
        return (
            <Lookup
                dataSource={lookupData}
                valueExpr="country"
                displayExpr="country"
                searchMode="startswith"
                searchPlaceholder="Type country name"
            />
        );
    }
}

export default App;

The Lookup UI component starts providing suggestions once an end user types the first character by default. Use the minSearchLength property to increase the number of characters that triggers suggestions.

jQuery
JavaScript
$(function() {
    $("#lookupContainer").dxLookup({
        // ...
        minSearchLength: 3
    });
});
Angular
HTML
TypeScript
<dx-lookup ...
    [minSearchLength]="3">
</dx-lookup>
import { DxLookupModule } from "devextreme-angular";
// ...
export class AppComponent {
    // ...
}
@NgModule({
    imports: [
        // ...
        DxLookupModule
    ],
    // ...
})
Vue
<template>
    <DxLookup ...
        :min-search-length="3"
    />
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxLookup } from 'devextreme-vue/lookup';

export default {
    components: {
        DxLookup
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { Lookup } from 'devextreme-react/lookup';

class App extends React.Component {
    render() {
        return (
            <Lookup ...
                minSearchLength={3}
            />
        );
    }
}

export default App;

There is a delay between the moment a user finishes typing and the moment the Lookup starts providing suggestions. To increase or descrease it, use the searchTimeout property. The delay is measured in milliseconds.

jQuery
JavaScript
$(function() {
    $("#lookupContainer").dxLookup({
        // ...
        searchTimeout: 500
    });
});
Angular
HTML
TypeScript
<dx-lookup ...
    [searchTimeout]="500">
</dx-lookup>
import { DxLookupModule } from "devextreme-angular";
// ...
export class AppComponent {
    // ...
}
@NgModule({
    imports: [
        // ...
        DxLookupModule
    ],
    // ...
})
Vue
<template>
    <DxLookup ...
        :search-timeout="500"
    />
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxLookup } from 'devextreme-vue/lookup';

export default {
    components: {
        DxLookup
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { Lookup } from 'devextreme-react/lookup';

class App extends React.Component {
    render() {
        return (
            <Lookup ...
                searchTimeout={500}
            />
        );
    }
}

export default App;

The Lookup UI component also clears previous search results before the drop-down menu is displayed by default. Assign false to the cleanSearchOnOpening property to keep them.

jQuery
JavaScript
$(function() {
    $("#lookupContainer").dxLookup({
        // ...
        cleanSearchOnOpening: false
    });
});
Angular
HTML
TypeScript
<dx-lookup ...
    [cleanSearchOnOpening]="false">
</dx-lookup>
import { DxLookupModule } from "devextreme-angular";
// ...
export class AppComponent {
    // ...
}
@NgModule({
    imports: [
        // ...
        DxLookupModule
    ],
    // ...
})
Vue
<template>
    <DxLookup ...
        :clean-search-on-opening="false"
    />
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxLookup } from 'devextreme-vue/lookup';

export default {
    components: {
        DxLookup
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { Lookup } from 'devextreme-react/lookup';

class App extends React.Component {
    render() {
        return (
            <Lookup ...
                cleanSearchOnOpening={false}
            />
        );
    }
}

export default App;

Assign false to the searchEnabled property if you need to disable searching.

jQuery
JavaScript
$(function() {
    $("#lookupContainer").dxLookup({
        // ...
        searchEnabled: false
    });
});
Angular
HTML
TypeScript
<dx-lookup ...
    [searchEnabled]="false">
</dx-lookup>
import { DxLookupModule } from "devextreme-angular";
// ...
export class AppComponent {
    // ...
}
@NgModule({
    imports: [
        // ...
        DxLookupModule
    ],
    // ...
})
Vue
<template>
    <DxLookup ...
        :search-enabled="false"
    />
</template>

<script>
import 'devextreme/dist/css/dx.light.css';

import { DxLookup } from 'devextreme-vue/lookup';

export default {
    components: {
        DxLookup
    }
}
</script>
React
import React from 'react';
import 'devextreme/dist/css/dx.light.css';

import { Lookup } from 'devextreme-react/lookup';

class App extends React.Component {
    render() {
        return (
            <Lookup ...
                searchEnabled={false}
            />
        );
    }
}

export default App;
See Also