I use md-autocomplete angular/material: 2.0.0-beta.5
in my Angular application. With the latest release the selected
method has been replaced by onSelectionChange
.
The first time a value from the drop down is selected, the associated method is triggered only once, but if I select a new value from the drop down, it is selected twice (the second time having the previous value).
The logic was working correctly with the previous version.
template
<md-autocomplete #panel="mdAutocomplete" [displayWith]="displayFn">
<md-option (onSelectionChange)="selected(country)" *ngFor="let country of filteredCountries | async" [value]="country">
<div class="selector-elements">
<span>
<img [src]="getFlagPath(country.code)" [width]="24" [height]="24" />
</span> {{ country.name }}
</div>
</md-option>
controller
export class CountrySelector implements OnInit, ControlValueAccessor {
// ...
initCountries() {
this.countryList = countryNames;
this.filteredCountries = this.formControlName.valueChanges
.startWith(null) //-> OnInit the countries are filtered by null, hence all results are returned.
.map(country => {
return country && typeof country === 'object' ? country.name : country
})
.map(name => name ? this.filter(name) : this.countryList.slice());
}
filter(val: string): ICountry[] {
//Regex to match with the first letters of the country name with the passed value.
return this.countryList.filter(country => new RegExp(`^${val}`, 'gi').test(country.name));
}
resetCountrySelection(){
let country = new Country();
this.formControlName.setValue(country);
this.propagateChange(country);
}
writeValue(country: Country): void {
if (country) {
this.formControlName.setValue(country);
}
}
selected(country: ICountry) {
// Here it gets triggered twice when a new element is chosen
this.propagateChange(country);
}
propagateChange = (_: any) => { };
registerOnChange(fn: any) {
this.propagateChange = fn;
}
}
What is happening is onSelectionChange fires both for the new selected, and the one being unselected, in that order. If you add the $event to your call like so
(onSelectionChange)="selected($event, country)"
you can then check if it is the selected one by looking at the source like this
selected(event: MdOptionSelectionChange, country: ICountry) {
if (event.source.selected) {
this.propagateChange(country);
}
}
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