`    constructor(private _api: ApiRequest,
            private _cookie: CookieService,
            public element: ElementRef,
            public renderer2: Renderer2,
            private _commonService: CommonService,
            private _router: Router) {
}`


 `let btn3=this.element.nativeElement.querySelector('#btn3');
    this.renderer2.listen(btn3,"click",()=> {
        //this.renderer2.setStyle(ul, "background", "blue");
        alert(22222);
    })

`

html 
<button type="button" id="btn3" class="tl-btn tl-btn-primary" >添加文字</button>