メインコンテンツまでスキップ
バージョン: v7

ion-select

shadow

Selects are form controls to select an option, or options, from a set of options. 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.

Labels

Labels should be used to describe the select. They can be used visually, and they will also be read out by screen readers when the user is focused on the select. This makes it easy for the user to understand the intent of the select. Select has several ways to assign a label:

Select has several options for supplying a label for the component:

  • label property: used for plaintext labels
  • label slot: used for custom HTML labels
  • aria-label: used to provide a label for screen readers but adds no visible label

Label Placement

Labels will take up the width of their content by default. Developers can use the labelPlacement property to control how the label is placed relative to the control. While the label property is used here, labelPlacement can also be used with the label slot.

Label Slot

While plaintext labels should be passed in via the label property, if custom HTML is needed, it can be passed through the label slot instead.

No Visible Label

If no visible label is needed, developers should still supply an aria-label so the select is accessible to screen readers.

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 select component's value receives the value of the selected option's value.

Keyboard interactions for single selection are described in the Keyboard Interactions section below.

Multiple Selection

By adding the multiple attribute to select, users are able to select multiple options. When multiple options can be selected, the alert or popover 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.

注記

The action-sheet interface is not supported with multiple selection.

Keyboard interactions for multiple selection are described in the Keyboard Interactions section below.

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.

Alert

Action Sheet

Popover

Responding to Interaction

The main ways of handling user interaction with the select are the ionChange, ionDismiss, and ionCancel events. See Events for more details on these and other events that select fires.

Console
Console messages will appear here when logged from the example above.

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.

Using compareWith

Console
Console messages will appear here when logged from the example above.

Object Values and Multiple Selection

Console
Console messages will appear here when logged from the example above.

Justification

Developers can use the justify property to control how the label and control are packed on a line.

Filled Selects

Material Design offers filled styles for a select. The fill property on the select can be set to either "solid" or "outline".

Since the fill styles visually defines the select container, selects that use fill should not be used in ion-item.

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.

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

Custom Toggle Icons

The icon that displays next to the select text can be set to any Ionicon using the toggleIcon and/or expandedIcon properties.

Icon Flip Behavior

By default, when the select is open, the toggle icon will automatically rotate on md mode and remain static on ios mode. This behavior can be customized using CSS.

The below example also uses a custom toggleIcon to better demonstrate the flip behavior on ios, since the default icon is vertically symmetrical.

Typeahead Component

Typeahead or autocomplete functionality can be built using existing Ionic components. We recommend using an ion-modal to make the best use of the available screen space.

Interfaces

SelectChangeEventDetail

interface SelectChangeEventDetail<T = any> {
value: T;
}

SelectCustomEvent

While not required, this interface can be used in place of the CustomEvent interface for stronger typing with Ionic events emitted from this component.

interface SelectCustomEvent<T = any> extends CustomEvent {
detail: SelectChangeEventDetail<T>;
target: HTMLIonSelectElement;
}

Migrating from Legacy Select Syntax

A simpler select syntax was introduced in Ionic 7.0. This new syntax reduces the boilerplate required to setup an select, resolves accessibility issues, and improves the developer experience.

Developers can perform this migration one select at a time. While developers can continue using the legacy syntax, we recommend migrating as soon as possible.

Using the Modern Syntax

Using the modern syntax involves two steps:

  1. Remove ion-label and use the label property on ion-select instead. The placement of the label can be configured using the labelPlacement property on ion-select.
  2. Move any usage of fill and shape from ion-item on to ion-select.
<!-- Label and Label Position -->

<!-- Before -->
<ion-item>
<ion-label position="floating">Favorite Fruit:</ion-label>
<ion-select>...</ion-select>
</ion-item>

<!-- After -->
<ion-item>
<ion-select label="Favorite Fruit:" label-placement="floating">...</ion-select>
</ion-item>


<!-- Fill -->

<!-- Before -->
<ion-item fill="outline" shape="round">
<ion-label position="floating">Favorite Fruit:</ion-label>
<ion-select>...</ion-select>
</ion-item>

<!-- After -->

<!-- Inputs using `fill` should not be placed in ion-item -->
<ion-select fill="outline" shape="round" label="Favorite Fruit:" label-placement="floating">...</ion-select>

Using the Legacy Syntax

Ionic uses heuristics to detect if an app is using the modern select syntax. In some instances, it may be preferable to continue using the legacy syntax. Developers can set the legacy property on ion-select to true to force that instance of the input to use the legacy syntax.

Accessibility

Keyboard Interactions

Ionic's keyboard interactions follow the implementation patterns of the web instead of the native iOS select for a consistent experience across all platforms.

These keyboard interactions apply to all ion-select elements when the following conditions are met:

  • The select is closed.
  • The select is focused.
  • The select is not disabled.
KeyDescription
EnterOpens the overlay and focuses on the first selected option. If there is no selected option, then it focuses on the first option.
SpaceOpens the overlay and focuses on the first selected option. If there is no selected option, then it focuses on the first option.

Single Selection

Single selection keyboard interaction follows the ARIA implementation patterns of a radio.

These keyboard interactions apply to ion-action-sheet, ion-alert, and ion-popover elements when the overlay is presented and focused.

KeyDescription
ArrowDownFocuses and selects the next option in the list. If there is no next option, selection will cycle to the first option.
ArrowLeftFocuses and selects the previous option in the list. If there is no previous option, selection will cycle to the last option.
ArrowRightFocuses and selects the next option in the list. If there is no next option, selection will cycle to the first option.
ArrowUpFocuses and selects the previous option in the list. If there is no previous option, selection will cycle to the last option.
EnterIf an option is focused, it will select the option. Overlays without an 'OK' button will commit the value immediately, dismiss the overlay and return focus to the ion-select element.

If the 'OK' button is focused, it will save the user's selection, dismiss the overlay and return focus to the ion-select element.
EscapeCloses the overlay without changing the submitted option. Returns the focus back to the ion-select element.
SpaceIf the focused radio button is not checked, unchecks the currently checked radio button and checks the focused radio button. Otherwise, does nothing. If the overlay does not have an 'OK' button, the value will be committed immediately and the overlay will dismiss.
TabMoves focus to the next focusable element (cancel button, 'OK' button, or either the selection or the first option) on the overlay. If the next focusable element is an option, then it will focus on the selected option, otherwise it will focus the first option.

Multiple Selection

Multiple selection keyboard interaction follows the ARIA implementation patterns of a checkbox.

These keyboard interactions apply to ion-alert and ion-popover elements when the overlay is presented and multiple selection is enabled.

KeyDescription
EnterWhen the 'OK' button is focused, it will save the user's selection, dismiss the overlay, and return focus to the ion-select element.
EscapeCloses the overlay without changing the submitted option(s). Returns the focus back to the ion-select element.
SpaceSelects or deselects the currently focused option. This does not deselect the other selected options. If the overlay does not have an 'OK' button, the value will be committed immediately.
TabMove focus to the next focusable element (cancel button, 'OK' button, or any of the options) on the overlay. If the next focusable element is the options list, then it should iterate through each option.

Properties

cancelText

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

color

DescriptionThe color to use from your application's color palette. Default options are: "primary", "secondary", "tertiary", "success", "warning", "danger", "light", "medium", and "dark". For more information on colors, see theming.

This property is only available when using the modern select syntax.
Attributecolor
Type"danger" | "dark" | "light" | "medium" | "primary" | "secondary" | "success" | "tertiary" | "warning" | string | undefined
Defaultundefined

compareWith

DescriptionThis property allows developers to specify a custom function or property name for comparing objects when determining the selected option in the ion-select. When not specified, the default behavior will use strict equality (===) for comparison.
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

expandedIcon

DescriptionThe toggle icon to show when the select is open. If defined, the icon rotation behavior in md mode will be disabled. If undefined, toggleIcon will be used for when the select is both open and closed.
Attributeexpanded-icon
Typestring | undefined
Defaultundefined

fill

DescriptionThe fill for the item. If "solid" the item will have a background. If "outline" the item will be transparent with a border. Only available in md mode.
Attributefill
Type"outline" | "solid" | undefined
Defaultundefined

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{}

justify

DescriptionHow to pack the label and select within a line. justify does not apply when the label and select are on different lines when labelPlacement is set to "floating" or "stacked". "start": The label and select will appear on the left in LTR and on the right in RTL. "end": The label and select will appear on the right in LTR and on the left in RTL. "space-between": The label and select will appear on opposite ends of the line with space between the two elements.
Attributejustify
Type"end" | "space-between" | "start"
Default'space-between'

label

DescriptionThe visible label associated with the select.

Use this if you need to render a plaintext label.

The label property will take priority over the label slot if both are used.
Attributelabel
Typestring | undefined
Defaultundefined

labelPlacement

DescriptionWhere to place the label relative to the select. "start": The label will appear to the left of the select in LTR and to the right in RTL. "end": The label will appear to the right of the select in LTR and to the left in RTL. "floating": The label will appear smaller and above the select when the select is focused or it has a value. Otherwise it will appear on top of the select. "stacked": The label will appear smaller and above the select regardless even when the select is blurred or has no value. "fixed": The label has the same behavior as "start" except it also has a fixed width. Long text will be truncated with ellipses ("..."). When using "floating" or "stacked" we recommend initializing the select with either a value or a placeholder.
Attributelabel-placement
Type"end" | "fixed" | "floating" | "stacked" | "start" | undefined
Default'start'

legacy

DescriptionSet the legacy property to true to forcibly use the legacy form control markup. Ionic will only opt components in to the modern form markup when they are using either the aria-label attribute or the label property. As a result, the legacy property should only be used as an escape hatch when you want to avoid this automatic opt-in behavior. Note that this property will be removed in an upcoming major release of Ionic, and all form components will be opted-in to using the modern form markup.
Attributelegacy
Typeboolean | undefined
Defaultundefined

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

shape

DescriptionThe shape of the select. If "round" it will have an increased border radius.
Attributeshape
Type"round" | undefined
Defaultundefined

toggleIcon

DescriptionThe toggle icon to use. Defaults to chevronExpand for ios mode, or caretDownSharp for md mode.
Attributetoggle-icon
Typestring | 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.
ionDismissEmitted when the overlay is dismissed.
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) => Promise<any>

CSS Shadow Parts

NameDescription
containerThe container for the selected text or placeholder.
iconThe select icon container.
labelThe label text describing the select.
placeholderThe text displayed in the select when there is no value.
textThe displayed value of the select.

CSS Custom Properties

NameDescription
--backgroundBackground of the select
--border-colorColor of the select border
--border-radiusRadius of the select border. A large radius may display unevenly when using fill="outline"; if needed, use shape="round" instead or increase --padding-start.
--border-styleStyle of the select border
--border-widthWidth of the select border
--highlight-color-focusedThe color of the highlight on the select when focused
--highlight-color-invalidThe color of the highlight on the select when invalid
--highlight-color-validThe color of the highlight on the select when valid
--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
--ripple-colorThe color of the ripple effect on MD mode.

Slots

NameDescription
endContent to display at the trailing edge of the select.
labelThe label text to associate with the select. Use the labelPlacement property to control where the label is placed relative to the select. Use this if you need to render a label with custom HTML.
startContent to display at the leading edge of the select.