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ion-select

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Selects are form controls to select an option, or options, from a set of options, similar to a native <select> element. When a user taps the select, a dialog appears with all of the options in a large, easy to select list.

A select should be used with child <ion-select-option> elements. If the child option is not given a value attribute then its text will be used as the value.

If value is set on the <ion-select>, the selected option will be chosen based on that value.

Interfaces#

By default, select uses ion-alert to open up the overlay of options in an alert. The interface can be changed to use ion-action-sheet or ion-popover by passing action-sheet or popover, respectively, to the interface property. Read on to the other sections for the limitations of the different interfaces.

Single Selection#

By default, the select allows the user to select only one option. The alert interface presents users with a radio button styled list of options. The action sheet interface can only be used with a single value select. The select component's value receives the value of the selected option's value.

Multiple Selection#

By adding the multiple attribute to select, users are able to select multiple options. When multiple options can be selected, the alert overlay presents users with a checkbox styled list of options. The select component's value receives an array of all of the selected option values.

Note: the action-sheet and popover interfaces will not work with multiple selection.

Object Value References#

When using objects for select values, it is possible for the identities of these objects to change if they are coming from a server or database, while the selected value's identity remains the same. For example, this can occur when an existing record with the desired object value is loaded into the select, but the newly retrieved select options now have different identities. This will result in the select appearing to have no value at all, even though the original selection in still intact.

By default, the select uses object equality (===) to determine if an option is selected. This can be overridden by providing a property name or a function to the compareWith property.

Select Buttons#

The alert supports two buttons: Cancel and OK. Each button's text can be customized using the cancelText and okText properties.

The action-sheet and popover interfaces do not have an OK button, clicking on any of the options will automatically close the overlay and select that value. The popover interface does not have a Cancel button, clicking on the backdrop will close the overlay.

Interface Options#

Since select uses the alert, action sheet and popover interfaces, options can be passed to these components through the interfaceOptions property. This can be used to pass a custom header, subheader, css class, and more.

See the ion-alert docs, ion-action-sheet docs, and ion-popover docs for the properties that each interface accepts.

Note: interfaceOptions will not override inputs or buttons with the alert interface.

Customization#

There are two units that make up the Select component and each need to be styled separately. The ion-select element is represented on the view by the selected value(s), or placeholder if there is none, and dropdown icon. The interface, which is defined in the Interfaces section above, is the dialog that opens when clicking on the ion-select. The interface contains all of the options defined by adding ion-select-option elements. The following sections will go over the differences between styling these.

Styling Select Element#

As mentioned, the ion-select element consists only of the value(s), or placeholder, and icon that is displayed on the view. To customize this, style using a combination of CSS and any of the CSS custom properties:

ion-select {  /* Applies to the value and placeholder color */  color: #545ca7;
  /* Set a different placeholder color */  --placeholder-color: #971e49;
  /* Set full opacity on the placeholder */  --placeholder-opacity: 1;}

Alternatively, depending on the browser support needed, CSS shadow parts can be used to style the select:

/* Set the width to the full container and center the content */ion-select {  width: 100%;
  justify-content: center;}
/* Set the flex in order to size the text width to its content */ion-select::part(placeholder),ion-select::part(text) {  flex: 0 0 auto;}
/* Set the placeholder color and opacity */ion-select::part(placeholder) {  color: #20a08a;  opacity: 1;}
/* * Set the font of the first letter of the placeholder * Shadow parts work with pseudo-elements, too! * https://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-elements */ion-select::part(placeholder)::first-letter {  font-size: 24px;  font-weight: 500;}
/* Set the text color */ion-select::part(text) {  color: #545ca7;}
/* Set the icon color and opacity */ion-select::part(icon) {  color: #971e49;  opacity: 1;}

Notice that by using ::part, any CSS property on the element can be targeted.

Styling Select Interface#

Customizing the interface dialog should be done by following the Customization section in that interface's documentation:

However, the Select Option does set a class for easier styling and allows for the ability to pass a class to the overlay option, see the Select Options documentation for usage examples of customizing options.

Usage#

Single Selection#

<ion-list>  <ion-list-header>    <ion-label>      Single Selection    </ion-label>  </ion-list-header>
  <ion-item>    <ion-label>Gender</ion-label>    <ion-select placeholder="Select One">      <ion-select-option value="f">Female</ion-select-option>      <ion-select-option value="m">Male</ion-select-option>    </ion-select>  </ion-item>
  <ion-item>    <ion-label>Hair Color</ion-label>    <ion-select value="brown" okText="Okay" cancelText="Dismiss">      <ion-select-option value="brown">Brown</ion-select-option>      <ion-select-option value="blonde">Blonde</ion-select-option>      <ion-select-option value="black">Black</ion-select-option>      <ion-select-option value="red">Red</ion-select-option>    </ion-select>  </ion-item>
</ion-list>

Multiple Selection#

<ion-list>  <ion-list-header>    <ion-label>      Multiple Selection    </ion-label>  </ion-list-header>
  <ion-item>    <ion-label>Toppings</ion-label>    <ion-select multiple="true" cancelText="Nah" okText="Okay!">      <ion-select-option value="bacon">Bacon</ion-select-option>      <ion-select-option value="olives">Black Olives</ion-select-option>      <ion-select-option value="xcheese">Extra Cheese</ion-select-option>      <ion-select-option value="peppers">Green Peppers</ion-select-option>      <ion-select-option value="mushrooms">Mushrooms</ion-select-option>      <ion-select-option value="onions">Onions</ion-select-option>      <ion-select-option value="pepperoni">Pepperoni</ion-select-option>      <ion-select-option value="pineapple">Pineapple</ion-select-option>      <ion-select-option value="sausage">Sausage</ion-select-option>      <ion-select-option value="Spinach">Spinach</ion-select-option>    </ion-select>  </ion-item>
  <ion-item>    <ion-label>Pets</ion-label>    <ion-select multiple="true" [value]="['bird', 'dog']">      <ion-select-option value="bird">Bird</ion-select-option>      <ion-select-option value="cat">Cat</ion-select-option>      <ion-select-option value="dog">Dog</ion-select-option>      <ion-select-option value="honeybadger">Honey Badger</ion-select-option>    </ion-select>  </ion-item></ion-list>

Objects as Values#

<ion-list>  <ion-list-header>    <ion-label>      Objects as Values (compareWith)    </ion-label>  </ion-list-header>
  <ion-item>    <ion-label>Users</ion-label>    <ion-select [compareWith]="compareWith">      <ion-select-option *ngFor="let user of users" [value]="user">{{user.first + ' ' + user.last}}</ion-select-option>    </ion-select>  </ion-item></ion-list>
import { Component } from '@angular/core';
interface User {  id: number;  first: string;  last: string;}
@Component({  selector: 'select-example',  templateUrl: 'select-example.html',  styleUrls: ['./select-example.css'],})export class SelectExample {  users: User[] = [    {      id: 1,      first: 'Alice',      last: 'Smith',    },    {      id: 2,      first: 'Bob',      last: 'Davis',    },    {      id: 3,      first: 'Charlie',      last: 'Rosenburg',    }  ];
  compareWith(o1: User, o2: User) {    return o1 && o2 ? o1.id === o2.id : o1 === o2;  }}

Objects as Values with Multiple Selection#

<ion-list>  <ion-list-header>    <ion-label>      Objects as Values (compareWith)    </ion-label>  </ion-list-header>
  <ion-item>    <ion-label>Users</ion-label>    <ion-select [compareWith]="compareWith" multiple="true">      <ion-select-option *ngFor="let user of users" [value]="user">{{user.first + ' ' + user.last}}</ion-select-option>    </ion-select>  </ion-item></ion-list>
import { Component } from '@angular/core';
interface User {  id: number;  first: string;  last: string;}
@Component({  selector: 'select-example',  templateUrl: 'select-example.html',  styleUrls: ['./select-example.css'],})export class SelectExample {  users: User[] = [    {      id: 1,      first: 'Alice',      last: 'Smith',    },    {      id: 2,      first: 'Bob',      last: 'Davis',    },    {      id: 3,      first: 'Charlie',      last: 'Rosenburg',    }  ];
  compareWith(o1: User, o2: User | User[]) {    if (!o1 || !o2) {      return o1 === o2;    }
    if (Array.isArray(o2)) {      return o2.some((u: User) => u.id === o1.id);    }
    return o1.id === o2.id;  }}

Interface Options#

<ion-list>  <ion-list-header>    <ion-label>      Interface Options    </ion-label>  </ion-list-header>
  <ion-item>    <ion-label>Alert</ion-label>    <ion-select [interfaceOptions]="customAlertOptions" interface="alert" multiple="true" placeholder="Select One">      <ion-select-option value="bacon">Bacon</ion-select-option>      <ion-select-option value="olives">Black Olives</ion-select-option>      <ion-select-option value="xcheese">Extra Cheese</ion-select-option>      <ion-select-option value="peppers">Green Peppers</ion-select-option>      <ion-select-option value="mushrooms">Mushrooms</ion-select-option>      <ion-select-option value="onions">Onions</ion-select-option>      <ion-select-option value="pepperoni">Pepperoni</ion-select-option>      <ion-select-option value="pineapple">Pineapple</ion-select-option>      <ion-select-option value="sausage">Sausage</ion-select-option>      <ion-select-option value="Spinach">Spinach</ion-select-option>    </ion-select>  </ion-item>
  <ion-item>    <ion-label>Popover</ion-label>    <ion-select [interfaceOptions]="customPopoverOptions" interface="popover" placeholder="Select One">      <ion-select-option value="brown">Brown</ion-select-option>      <ion-select-option value="blonde">Blonde</ion-select-option>      <ion-select-option value="black">Black</ion-select-option>      <ion-select-option value="red">Red</ion-select-option>    </ion-select>  </ion-item>
  <ion-item>    <ion-label>Action Sheet</ion-label>    <ion-select [interfaceOptions]="customActionSheetOptions" interface="action-sheet" placeholder="Select One">      <ion-select-option value="red">Red</ion-select-option>      <ion-select-option value="purple">Purple</ion-select-option>      <ion-select-option value="yellow">Yellow</ion-select-option>      <ion-select-option value="orange">Orange</ion-select-option>      <ion-select-option value="green">Green</ion-select-option>    </ion-select>  </ion-item>
</ion-list>
import { Component } from '@angular/core';
@Component({  selector: 'select-example',  templateUrl: 'select-example.html',  styleUrls: ['./select-example.css'],})export class SelectExample {  customAlertOptions: any = {    header: 'Pizza Toppings',    subHeader: 'Select your toppings',    message: '$1.00 per topping',    translucent: true  };
  customPopoverOptions: any = {    header: 'Hair Color',    subHeader: 'Select your hair color',    message: 'Only select your dominant hair color'  };
  customActionSheetOptions: any = {    header: 'Colors',    subHeader: 'Select your favorite color'  };}

Properties#

cancelText#

DescriptionThe text to display on the cancel button.
Attributecancel-text
Typestring
Default'Cancel'

compareWith#

DescriptionA property name or function used to compare object values
Attributecompare-with
Type((currentValue: any, compareValue: any) => boolean) | null | string | undefined
Defaultundefined

disabled#

DescriptionIf true, the user cannot interact with the select.
Attributedisabled
Typeboolean
Defaultfalse

interface#

DescriptionThe interface the select should use: action-sheet, popover or alert.
Attributeinterface
Type"action-sheet" | "alert" | "popover"
Default'alert'

interfaceOptions#

DescriptionAny additional options that the alert, action-sheet or popover interface
can take. See the ion-alert docs, the
ion-action-sheet docs and the
ion-popover docs for the
create options for each interface.

Note: interfaceOptions will not override inputs or buttons with the alert interface.
Attributeinterface-options
Typeany
Default{}

mode#

DescriptionThe mode determines which platform styles to use.
Attributemode
Type"ios" | "md"
Defaultundefined

multiple#

DescriptionIf true, the select can accept multiple values.
Attributemultiple
Typeboolean
Defaultfalse

name#

DescriptionThe name of the control, which is submitted with the form data.
Attributename
Typestring
Defaultthis.inputId

okText#

DescriptionThe text to display on the ok button.
Attributeok-text
Typestring
Default'OK'

placeholder#

DescriptionThe text to display when the select is empty.
Attributeplaceholder
Typestring | undefined
Defaultundefined

selectedText#

DescriptionThe text to display instead of the selected option's value.
Attributeselected-text
Typenull | string | undefined
Defaultundefined

value#

Descriptionthe value of the select.
Attributevalue
Typeany
Defaultundefined

Events#

NameDescription
ionBlurEmitted when the select loses focus.
ionCancelEmitted when the selection is cancelled.
ionChangeEmitted when the value has changed.
ionFocusEmitted when the select has focus.

Methods#

open#

DescriptionOpen the select overlay. The overlay is either an alert, action sheet, or popover,
depending on the interface property on the ion-select.
Signatureopen(event?: UIEvent | undefined) => Promise<any>

CSS Shadow Parts#

NameDescription
iconThe select icon container.
placeholderThe text displayed in the select when there is no value.
textThe displayed value of the select.

CSS Custom Properties#

NameDescription
--padding-bottomBottom padding of the select
--padding-endRight padding if direction is left-to-right, and left padding if direction is right-to-left of the select
--padding-startLeft padding if direction is left-to-right, and right padding if direction is right-to-left of the select
--padding-topTop padding of the select
--placeholder-colorColor of the select placeholder text
--placeholder-opacityOpacity of the select placeholder text
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