SelectMultipleControlValueAccessor
directive
stable
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.
API
class SelectMultipleControlValueAccessor extends BuiltInControlValueAccessor implements ControlValueAccessor { @Input() set compareWith(value: (o1: any, o2: any) => boolean);}
compareWith
(o1: any, o2: any) => booleanTracks the option comparison algorithm for tracking identities when checking for changes.
Description
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.
Exported by
Usage Notes
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"> @for(country of countries; track $index) { <option [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.
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