角度8 ng-bootstrap 5.2.2反应形式，NgbDatepicker不起作用

Question

为什么Bootstrap日期选择器不能使用反应式表单？

<input formControlName="startDate" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.startDate.errors }" ngbDatepicker #d />

export class AddEventComponent implements OnInit {

@ViewChild('d', { read: NgbDatepicker, static: true }) d: NgbDatepicker;

如果我放：

<input formControlName="startDate" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.startDate.errors }" ngbDatepicker #d="ngbDatepicker" />

我收到错误消息：There is no directive with "exportAs" set to "ngbDatepicker"。