Angular6-将服务调用作为引用传递给子组件

我正在开发一个自定义选择组件，它从其父组件发出的服务调用接收数据。如果给定的调用由于任何原因失败，我需要将重试函数传递给select（服务调用本身）。调用了函数，但未按预期传递

this

：

我的父组件：

<div class="form-group row mb-4">
    <div class="col-md-12 col-12">
      <custom-select [field]="fields.bank" [formControlName]="fields.bank.controlName" [errors]="submitted ? formControls.bank.errors : null">
      </custom-select>
    </div>
 </div>

custom-select.component.html

<div class="select__error">
  <span>
     <a class="select__retry-link" (click)="retry()">retry</a>.
  </span>
</div>

服务台

constructor(
    public httpClient: HttpClient, //<-- it was initially private, but public also doesn't work.
  ) { }

public queryAll(): Observable<Bank[]> {
  return this //<-- this is referring to CustomSelectComponent, not to the service itself. Throws error.
    .httpClient
    .get<BankResponse[]>(environment.apiUrls.banks)
    .pipe(map(result => {
      return this.mapToBankModels(result);
    }));
}

构造函数(
公共httpClient:httpClient，//您可以进行
queryAll

publicqueryall=（）：可观察=>{
还这个
.httpClient
.get（environment.apirls.banks）
.pipe（映射（结果=>{
返回此.mapToBankModels（结果）；
}));
}

或者您可以使用
Function.prototype.call（）
指定此
的值
retry(event?: Event): void {
    if (event) { event.preventDefault(); }
    if (typeof (this.retryFunction) === 'function') {
      this.retryFunction();
    }
  }

constructor(
    public httpClient: HttpClient, //<-- it was initially private, but public also doesn't work.
  ) { }

public queryAll(): Observable<Bank[]> {
  return this //<-- this is referring to CustomSelectComponent, not to the service itself. Throws error.
    .httpClient
    .get<BankResponse[]>(environment.apiUrls.banks)
    .pipe(map(result => {
      return this.mapToBankModels(result);
    }));
}

public queryAll = (): Observable<Bank[]> => {
  return this
    .httpClient
    .get<BankResponse[]>(environment.apiUrls.banks)
    .pipe(map(result => {
      return this.mapToBankModels(result);
    }));
}