小编use*_*496的帖子

如何使用Angular或打字稿来大写字符串的第一个字母？

我是打字稿的新手,我得到了这个错误

类型'Observable'不能分配给'IProduct []'.'Observable'类型中缺少属性'includes'.

我的服务类是:

getProducts() : Observable<IProduct[]> {
    return this._http.get<IProduct[]>(this._productUrl)
    .do(data=>console.log('All: ' + JSON.stringify(data)))
    .catch(this.handleError);
}


private handleError(err : HttpErrorResponse){
    console.log(err.message);
    return Observable.throw(err.message)
}

它在哪里错了,我应该怎么做才能解决它？

我有一个对象：

export class ReccurrenceModel {
    fromDate: Date;
    toDate: Date;
    weeklyReccurrence: number;
    state: State;
    isMonday: boolean;
    isTuesday: boolean;
    isWednesday: boolean;
    isThursday: boolean;
    isFriday: boolean;
    fromDateToReturn: Date;
    toDateToReturn: Date;
}

我像这样使用它

  if (this.reccurrenceSelected === true) {
      this.reccurrence.isMonday = this.mondaySelected;
      this.reccurrence.isTuesday = this.tuesdaySelected;
      this.reccurrence.isWednesday = this.wednesdaySelected;
      this.reccurrence.isThursday = this.thursdaySelected;
      this.reccurrence.isFriday = this.fridaySelected;
}

我想为它们设置一个默认值 - false 因为如果我不在 UI 中设置它们，它们将是未定义的，我不想要那样。

如何在打字稿中设置布尔值的默认值？

我正在使用 bootstrap4 navs 和一个表单，我试图将 css 类更改为显示：none; 对于每个未选择的选项卡，我尝试使用 ngClass 来实现此目的，但没有起作用 stackblitz demo

  <ul class="nav nav-tabs" id="myTab" role="tablist">
    <li class="nav-item">
      <a class="nav-link active" id="itemSummary-tab" data-toggle="tab" href="#itemSummary" role="tab" aria-controls="itemSummary" aria-selected="true">Item Summary</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" id="details-tab" data-toggle="tab" href="#details" role="tab" aria-controls="details" aria-selected="false">Details</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" id="measurement-tab" data-toggle="tab" href="#measurement" role="tab" aria-controls="measurement" aria-selected="false">Measurement</a>
    </li>
  </ul>

     <div class="tab-pane fade show active" ngClass="!active? display:none" id="itemSummary" role="tabpanel" aria-labelledby="itemSummary-tab"> 
    ....
    </div>
  <div class="tab-pane fade" id="measurement" ngClass="!active? display:none" role="tabpanel" aria-labelledby="measurement-tab">
...
</div>
  <div class="tab-pane fade" id="details" role="tabpanel" aria-labelledby="details-tab"> …

我有一个带有复选框和按钮的 Angular 组件，如果未选中该复选框，则应禁用该按钮。什么是正确的方法？

<div class="form-check my-5">
  <input type="checkbox" class="form-check-input id="agreements">
  <label class="form-check-label" for="agreements">I have signed the agreements</label>
</div>

<button type="button" class="btn btn-outline-danger">Continue</button>

我试图将一个日期对象推入一个数组,我得到这个错误"无法读取属性'推送'未定义".

export class CalendarComponent { 
days: Date[]

showMonths() {

 const interval = new Interval();

    interval.fromMonth  = this.selectedFromMonth.number;
    interval.fromYear = this.selectedFromYear.number;
    interval.toMonth = this.selectedToMonth.number;
    interval.toYear = this.selectedToYear.number;

    for (let i = interval.fromMonth - 1; i < 11; i++) {
      const day = new Date(interval.fromYear, i, 1);
       this.days.push(day);
      // console.log(day);
      // days.push(day);
    }

    // console.log(day);
}

如果'days'已经是一个数组并且'day'没有未定义,为什么我会收到此错误？

如何将字符串var numbers = "2016, 2017, 2018";转换为List<int>？

我试过这个:

List<int> years = Int32.Parse(yearsString.Split(',')).ToList();

但是我收到以下错误消息:

无法从string []转换为字符串.