<mat-select #matRef [formControl]="cMultiCtrl" [multiple]="true" required (selectionChange)="selectionChange($event)">
<mat-option>
<ngx-mat-select-search placeholderLabel="Search" noEntriesFoundLabel="No Matching Value Found" [formControl]="cMultiFilterCtrl"></ngx-mat-select-search>
</mat-option>
<mat-option *ngFor="let val of filteredCMulti | async" [value]="val.value">
{{val.name}}
</mat-option>
</mat-select>
@ViewChild('matRef') matRef: MatSelect;
clear() {
this.matRef.options.forEach((data: MatOption) => data.deselect());
}