无限滚动在角度6

Question

我使用了angular6的无限滚动。但它只能在第一次使用。但是，当我更改其他选项卡并滚动时，滚动功能未触发。 看到我下面的代码。请有人帮我...

    <div class="row">
        <tabset style="width:100%">
            <tab heading="All" id="tab1"  (select)="onSelect($event)"></tab>
            <tab heading="Draft" (select)="onSelect($event)"></tab>
            <tab heading="Published" (select)="onSelect($event)"></tab>
            <tab heading="Consumed" (select)="onSelect($event)"></tab>
        </tabset>

        <div class="container">
            <div class="row tttt" infiniteScroll [infiniteScrollDistance]="8" [infiniteScrollThrottle]="50" (scrolled)="onScroll()" [scrollWindow]="false" style="height:500px; overflow-y: scroll;">
                <div *ngFor="let item of  myExamList" class="col-md-4" style="margin-top: 10px;">

                     <div class="ibox-content"  >


                            <div class="box-header with-border">
                                <a routerLink="/resouceauthoring/exam/{{item.ExamRowId}}">
                                    <h3> {{ item.Title }}</h3>
                                </a>    
                            </div>
                    </div>
                </div>
            </div>
        </div>
    </div>


// Scroll Function
    onScroll() {
        this.currentNowPage = this.currentNowPage + 1;
        if (this.maxPage >= this.currentNowPage)
        {
            this.ScrollBindingExamList();
        }  
    }