如何在 angular 中动态删除 MAT_DATE_RANGE_SELECTION_STRATEGY

Question

我正在尝试使用自定义 MAT_DATE_RANGE_SELECTION_STRATEGY 在 angular 中实现日期选择器。这允许用户 select 14 天的范围。

使用以下代码（直接从 angular 文档中取出）来实施自定义策略

@Injectable()
export class FourteenDayRangeSelectionStrategy<D> implements MatDateRangeSelectionStrategy<D> {
  constructor(private _dateAdapter: DateAdapter<D>) {}

  selectionFinished(date: D | null): DateRange<D> {
    return this._createFourteeDayRange(date);
  }

  createPreview(activeDate: D | null): DateRange<D> {
    return this._createFourteeDayRange(activeDate);
  }

  private _createFourteeDayRange(date: D | null): DateRange<D> {
    if (date) {
      const start = this._dateAdapter.addCalendarDays(date, 0);
      const end = this._dateAdapter.addCalendarDays(date, 13);
      return new DateRange<D>(start, end);
    }

    return new DateRange<D>(null, null);
  }
}

并将其注入到组件中，如下所示。

@Component({
  selector: 'app-awesomecomponent',
  templateUrl: './awesomecomponent.component.html',
  styleUrls: ['./awesomecomponent.component.css'],
  providers: [{
    provide: MAT_DATE_RANGE_SELECTION_STRATEGY,
    useClass: FourteenDayRangeSelectionStrategy
  }]
})

然而，当用户select选中允许自定义日期范围复选框（如上图所示）时，我希望禁用自定义策略并允许用户选择任何日期范围。

我怎样才能实现这个功能？我假设，我们需要从组件中动态删除 below 以允许任何日期 selection。但是我不知道该怎么做。

providers: [{
    provide: MAT_DATE_RANGE_SELECTION_STRATEGY,
    useClass: FourteenDayRangeSelectionStrategy
  }]

请帮忙。

Answer 1

您在 github 中有 MatDateRangeSelectionStrategy 的来源，因此您可以使用变量来激活或关闭策略。

export class FourteenDaySelectionStrategy<D>
  implements MatDateRangeSelectionStrategy<D>
{
  constructor(private _dateAdapter: DateAdapter<D>) {}
  off: boolean = false; //--use a variable "off"
  selectionFinished(date: D | null, currentRange: DateRange<D>): DateRange<D> {
    if (!this.off) return this._createFourteenDayRange(date);

    //see that al the code below is the code of the github
    let { start, end } = currentRange;

    if (start == null) {
      start = date;
    } else if (
      end == null &&
      date &&
      this._dateAdapter.compareDate(date, start) >= 0
    ) {
      end = date;
    } else {
      start = date;
      end = null;
    }

    return new DateRange<D>(start, end);
  }

  createPreview(
    activeDate: D | null,
    currentRange: DateRange<D>
  ): DateRange<D> {
    if (!this.off) return this._createFourteenDayRange(activeDate);

    //see that al the code below is the code of the github
    let start: D | null = null;
    let end: D | null = null;

    if (currentRange.start && !currentRange.end && activeDate) {
      start = currentRange.start;
      end = activeDate;
    }

    return new DateRange<D>(start, end);
  }

  private _createFourteenDayRange(date: D | null): DateRange<D> {
    if (date) {
      const start = date;
      const end = this._dateAdapter.addCalendarDays(date, 14);
      return new DateRange<D>(start, end);
    }

    return new DateRange<D>(null, null);
  }

现在，您需要注入 MatDateRangeSelection 并使用 getter 更改变量的值 off

  constructor(
    @Inject(MAT_DATE_RANGE_SELECTION_STRATEGY)
    private rg: FourteenDaySelectionStrategy<any>
  ) {}
  get customRange() {
    return this.rg.off;
  }
  set customRange(value) {
    this.rg.off = value;
  }

带有 [(ngModel)] 的复选框完成代码

见stackblitz

如何在 angular 中动态删除 MAT_DATE_RANGE_SELECTION_STRATEGY

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