Javascript IONAL viewchild变量在ng开关中不可用

我正在学习以下代码

@ViewChild(MultiImageUploadComponent) multiImageUpload: MultiImageUploadComponent;

但是，当我尝试使用ion segment和ng开关实现选项卡时，我无法从第二个选项卡访问multiImageUpload。像这样。每次切换到第二个选项卡时，我都会收到错误co.multiImageUpload未定义

<ion-segment [(ngModel)]="defaultTab">
    <ion-segment-button value="managePhotos">
        Manage Photos
    </ion-segment-button>
    <ion-segment-button value="addPhotos">
        Add Photos
    </ion-segment-button>

  </ion-segment>
  <div [(ngSwitch)]="defaultTab">
        <ion-grid *ngSwitchCase="'managePhotos'">
          <ion-row>
            <ion-col col-6 col-md-4 col-xl-3 *ngFor="let photo of storyData.photos">
              <div class="image-container" [style.background-image]="'url('')'" (click)='photo()'></div>
            </ion-col>
          </ion-row>
        </ion-grid>
        <ion-grid *ngSwitchCase="'addPhotos'">
            <ion-row>
                <multi-image-upload></multi-image-upload>
                <button ion-button block (click)="newStory()" *ngIf="!multiImageUpload.isUploading && !uploadFinished">
                    <ion-icon name="checkmark"></ion-icon>
                    Upload
                </button>
                <button ion-button block (click)="cancel()" color="danger" *ngIf="multiImageUpload.isUploading && !uploadFinished">
                    <ion-icon name="close"></ion-icon>
                    Cancel
                </button>
            </ion-row>
        </ion-grid>
  </div>

管理照片
添加照片
上传
取消

尝试放置#id并通过id访问组件。您的意思是在

addPhotos

段中您无法访问组件吗？在addPhotos部分中是