SelectMultipleControlValueAccessor

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< @angular/formsAngular/docs/8/api/forms/selectmultiplecontrolvalueaccessor


SelectMultipleControlValueAccessor

directive

The ControlValueAccessor for writing multi-select control values and listening to multi-select control changes. The value accessor is used by the FormControlDirective, FormControlName, and NgModel directives.

See also

  • SelectControlValueAccessor

NgModules

Selectors

  • select[multiple][formControlName]
  • select[multiple][formControl]
  • select[multiple][ngModel]

Properties

Property Description
value: any The current value
onChange: (_: any) => { } The registered callback function called when a change event occurs on the input element.
onTouched: () => { } The registered callback function called when a blur event occurs on the input element.
@Input()compareWith: (o1: any, o2: any) => boolean

Write-Only Tracks the option comparison algorithm for tracking identities when checking for changes.

Description

Using a multi-select control

The follow example shows you how to use a multi-select control with a reactive form.

const countryControl = new FormControl();
<select multiple name="countries" [formControl]="countryControl">
  <option *ngFor="let country of countries" [ngValue]="country">
    {{ country.name }}
  </option>
</select>

Customizing option selection

To customize the default option comparison algorithm, <select> supports compareWith input. See the SelectControlValueAccessor for usage.

Methods

Sets the "value" property on one or of more of the select's options.

writeValue(value: any): void

Parameters
value any The value
Returns

void


Registers a function called when the control value changes and writes an array of the selected options.

registerOnChange(fn: (value: any) => any): void

Parameters
fn (value: any) => any The callback function
Returns

void


Registers a function called when the control is touched.

registerOnTouched(fn: () => any): void

Parameters
fn () => any The callback function
Returns

void


Sets the "disabled" property on the select input element.

setDisabledState(isDisabled: boolean): void

Parameters
isDisabled boolean The disabled value
Returns

void



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Licensed under the Creative Commons Attribution License 4.0.
https://v8.angular.io/api/forms/SelectMultipleControlValueAccessor