如何在angular 4 autoComplete材质中调用closePanel

import { MdAutocomplete } from '@angular/material';

@Component({
 template:'
             <input type="text" [mdAutocomplete]="auto"/>
             <md-autocomplete #auto="mdAutocomplete" #autoComplete>
             <md-option>
               Some Options
             </md-option>
          </md-autocomplete>'
})

export class AutoComplete {
 @ViewChild('autoComplete') autoComplete: MdAutocomplete;

 closeAuto() {
   this.autoComplete.closePanel();
 }
}

它不是完整的代码,但想法是在方法中调用closePanel. closePanel在https://material.angular.io/components/autocomplete/api上列为方法,但无法正常工作.它说找不到方法.

尝试过这种方法

import { MdAutocompleteTrigger } from '@angular/material';

@Component({
 template:'
             <input #autoCompleteInput type="text" [mdAutocomplete]="auto"/>
             <md-autocomplete #auto="mdAutocomplete" #autoComplete>
             <md-option>
               Some Options
             </md-option>
          </md-autocomplete>'
})

export class AutoComplete {
 @ViewChild('autoCompleteInput') autoComplete: MdAutocompleteTrigger;

 closeAuto() {
   this.autoComplete.closePanel();
 }
}