ion-select
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 labelslabel
slot: used for custom HTML labelsaria-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.
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:
- Remove
ion-label
and use thelabel
property onion-select
instead. The placement of the label can be configured using thelabelPlacement
property onion-select
. - Move any usage of
fill
andshape
fromion-item
on toion-select
.
- JavaScript
- Angular
- React
- Vue
<!-- 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>
<!-- 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:" labelPlacement="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:" labelPlacement="floating">...</ion-select>
{/* Label and Label Position */}
{/* Before */}
<IonItem>
<IonLabel position="floating">Favorite Fruit:</IonLabel>
<IonSelect>...</IonSelect>
</IonItem>
{/* After */}
<IonItem>
<IonSelect label="Favorite Fruit:" labelPlacement="floating">...</IonSelect>
</IonItem>
{/* Fill */}
{/* Before */}
<IonItem fill="outline" shape="round">
<IonLabel position="floating">Favorite Fruit:</IonLabel>
<IonSelect>...</IonSelect>
</IonItem>
{/* After */}
{/* Inputs using `fill` should not be placed in IonItem */}
<IonSelect fill="outline" shape="round" label="Favorite Fruit:" labelPlacement="floating">...</IonSelect>
<!-- 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.
Key | Description |
---|---|
Enter | Opens the overlay and focuses on the first selected option. If there is no selected option, then it focuses on the first option. |
Space | Opens 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.
Key | Description |
---|---|
ArrowDown | Focuses and selects the next option in the list. If there is no next option, selection will cycle to the first option. |
ArrowLeft | Focuses and selects the previous option in the list. If there is no previous option, selection will cycle to the last option. |
ArrowRight | Focuses and selects the next option in the list. If there is no next option, selection will cycle to the first option. |
ArrowUp | Focuses and selects the previous option in the list. If there is no previous option, selection will cycle to the last option. |
Enter | If 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. |
Escape | Closes the overlay without changing the submitted option. Returns the focus back to the ion-select element. |
Space | If 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. |
Tab | Moves 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.
Key | Description |
---|---|
Enter | When the 'OK' button is focused, it will save the user's selection, dismiss the overlay, and return focus to the ion-select element. |
Escape | Closes the overlay without changing the submitted option(s). Returns the focus back to the ion-select element. |
Space | Selects 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. |
Tab | Move 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
Description | キャンセルボタンに表示するテキストです。 |
Attribute | cancel-text |
Type | string |
Default | 'Cancel' |
color
Description | The 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. |
Attribute | color |
Type | "danger" | "dark" | "light" | "medium" | "primary" | "secondary" | "success" | "tertiary" | "warning" | string | undefined |
Default | undefined |
compareWith
Description | This 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. |
Attribute | compare-with |
Type | ((currentValue: any, compareValue: any) => boolean) | null | string | undefined |
Default | undefined |
disabled
Description | true の場合、ユーザはセレクトと対話することができません。 |
Attribute | disabled |
Type | boolean |
Default | false |
expandedIcon
Description | The 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. |
Attribute | expanded-icon |
Type | string | undefined |
Default | undefined |
fill
Description | The 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. |
Attribute | fill |
Type | "outline" | "solid" | undefined |
Default | undefined |
interface
Description | selectが使用するインターフェース。action-sheet, popoverまたは alert`. |
Attribute | interface |
Type | "action-sheet" | "alert" | "popover" |
Default | 'alert' |
interfaceOptions
Description | Any 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. |
Attribute | interface-options |
Type | any |
Default | {} |
justify
Description | How 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. |
Attribute | justify |
Type | "end" | "space-between" | "start" |
Default | 'space-between' |
label
Description | The 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. |
Attribute | label |
Type | string | undefined |
Default | undefined |
labelPlacement
Description | Where 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 . |
Attribute | label-placement |
Type | "end" | "fixed" | "floating" | "stacked" | "start" | undefined |
Default | 'start' |
legacy
Description | Set 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. |
Attribute | legacy |
Type | boolean | undefined |
Default | undefined |
mode
Description | modeは、どのプラットフォームのスタイルを使用するかを決定します。 |
Attribute | mode |
Type | "ios" | "md" |
Default | undefined |
multiple
Description | true の場合、selectは複数の値を受け入れることができる。 |
Attribute | multiple |
Type | boolean |
Default | false |
name
Description | フォームデータとともに送信されるコントロールの名前。 |
Attribute | name |
Type | string |
Default | this.inputId |
okText
Description | okボタンに表示するテキストです。 |
Attribute | ok-text |
Type | string |
Default | 'OK' |
placeholder
Description | セレクトが空のときに表示するテキストです。 |
Attribute | placeholder |
Type | string | undefined |
Default | undefined |
selectedText
Description | 選択されたオプションの値の代わりに表示するテキストです。 |
Attribute | selected-text |
Type | null | string | undefined |
Default | undefined |
shape
Description | セレクトの形状を指定します。round の場合、境界線の半径が大きくなります。 |
Attribute | shape |
Type | "round" | undefined |
Default | undefined |
toggleIcon
Description | The toggle icon to use. Defaults to chevronExpand for ios mode, or caretDownSharp for md mode. |
Attribute | toggle-icon |
Type | string | undefined |
Default | undefined |
value
Description | セレクトの値です。 |
Attribute | value |
Type | any |
Default | undefined |
Events
Name | Description | Bubbles |
---|---|---|
ionBlur | セレクトのフォーカスが外れたときに発行されます。 | true |
ionCancel | 選択がキャンセルされたときに発行されます。 | true |
ionChange | 値が変更されたときに発行されます。 | true |
ionDismiss | オーバーレイが解除されたときに発行されます。 | true |
ionFocus | セレクトにフォーカスが当たったときに発行されます。 | true |
Methods
open
Description | Open the select overlay. The overlay is either an alert, action sheet, or popover, depending on the interface property on the ion-select . |
Signature | open(event?: UIEvent) => Promise<any> |
CSS Shadow Parts
Name | Description |
---|---|
container | 選択テキストまたはプレースホルダーのコンテナ。 |
icon | セレクトアイコンのコンテナです。 |
label | セレクトを表すラベルテキスト。 |
placeholder | 値がないときにセレクトに表示されるテキスト。 |
text | セレクトの表示値です。 |
CSS Custom Properties
Name | Description |
---|---|
--background | セレクトの背景 |
--border-color | セレクトボーダーの色 |
--border-radius | 選択枠の半径。fill="outline "を使う場合、半径が大きいと表示が不 均一になることがあります。 |
--border-style | セレクトボーダーのスタイル |
--border-width | セレクトボーダ ーの幅 |
--highlight-color-focused | フォーカス時のセレクトのハイライトの色 |
--highlight-color-invalid | 無効時のセレクトのハイライトの色 |
--highlight-color-valid | 有効時のセレクトのハイライトの色 |
--padding-bottom | セレクトのBottom Padding |
--padding-end | セレクトの方向が左から右の場合はRight Padding、右から左の場合はLeft Paddingを行う |
--padding-start | セレクトの方向が左から右の場合はLeft Padding、右から左の場合はRight Padding |
--padding-top | セレクトのTop Padding |
--placeholder-color | セレクトPlaceholderテキストの色 |
--placeholder-opacity | 選択Placeholderテキストの不透明度 |
--ripple-color | MDモード時のリップルエフェクトの色です。 |
Slots
Name | Description |
---|---|
end | セレクトの最後尾に表示するコンテンツ。 |
label | セレクトに関連付けるラベルテキスト。labelPlacement`プロパティを使用して、selectに対するラベルの位置を制御します。ラベルをカスタムHTMLでレンダリングする必要がある場合に使用します。 |
start | セレクトの最先端に表示するコンテンツ。 |