自动完成不是有角度的？

Elements = [
    { id: 1,name: 'Hydrogen' },{ id: 2,name: 'Helium' },{ id: 3,name: 'Lithium' }


  ];

HTML

<mat-form-field class="example-full-width">
    <input type="text" placeholder="Pick one" aria-label="Number" matInput [formControl]="name"
     [matAutocomplete]="auto"  [errorStateMatcher]="matcher">
    <mat-autocomplete autoActiveFirstOption #auto="matAutocomplete" (selectionChange)="elementSelectionChange($event)">
      <mat-option *ngFor="let Element of filteredOptions | async" [value]="Element.name">
        {{ Element.name}}
      </mat-option>
    </mat-autocomplete>
        <mat-error *ngIf="myForm.hasError('required','name')">Please choose an name</mat-error>
  </mat-form-field>

零件

export class DialogOverviewExampleDialog implements OnInit{
  Elements = [
    { id: 1,name: 'Lithium' }


  ];

  matcher = new MyErrorStateMatcher();
  selectedElementSymbol: any;
  myForm: FormGroup;
  symbol;
  //name;
  name: FormControl = new FormControl();
  id;
  filteredOptions: Observable<string[]>;
  OnInit() {
    this.filteredOptions = this.name.valueChanges.pipe(
      startWith(''),map(val => this.filter(val))
    );
  }

  filter(val: any): any[] {
    return this.Elements.filter(Element => {
      return Element.name.toLowerCase().indexOf(val.toLowerCase()) > -1;
    });
  }
  constructor(
    public dialogRef: MatDialogRef<DialogOverviewExampleDialog>,@Inject(MAT_DIALOG_DATA) public data: any,private formBuilder: FormBuilder) {


  }


}

这是我到目前为止所建立的.自动完成功能不起作用,但有人帮助我继续前进

demo