javascript – Angular2’this’未定义

export class CRListComponent extends ListComponent<CR> implements OnInit {

    constructor(
        private router: Router,private crservice: CRservicE) {
        super();
    }

    ngOnInit():any {
        this.getCount(new Object(),this.crservice.getCount);
    }

ListComponent代码是这样的

@Component({})
export abstract class ListComponent<T extends Listable> {

    protected getCount(event: any,countFunction: Function){
        let filters = this.parseFilters(event.filters);
        countFunction(filters)
            .subscribe(
                count => {
                    this.@R_199_10586@lItems = count;
                },error => console.log(error)
            );
    }

CRservice的相应服务代码片段是这样的：

getCount(filters) {
    var queryParams = JSON.Stringify(
        {
            c : 'true',q : filters
        }
    );

    return this.createQuery(queryParams)
        .map(res => res.json())
        .catch(this.handleError);
}

现在当我的ngOnInit()运行时,我收到一个错误：

所以基本上,返回this.createQuery(queryParams)语句中的this将为null.有人知道这有可能吗？