map.foreachfeatureatpixel() 在角度打字稿开放层 7 中不起作用

Question

代码在普通 Javascript 中工作得很好，但在 typescript(Angular) 中它抛出了一个错误，即 this.map.foreachfeatuatpixel(), this.map 未定义，无法读取未定义的属性

这是我的代码：

public selected: Collection<Feature<any>> = new Collection();
multiSelectFeatures(): void {
  this.clearInteractions();
  this.ClearSelection();
  if (this.selected instanceof Collection) {
    this.selected.forEach(function (feature) {
      feature.setStyle(undefined);
    });
    this.selected.clear();
  }
  this.map.on("singleclick", this.getmultiplefeaturesatpixel);
}

getmultiplefeaturesatpixel(evt: { pixel: Pixel }): void {
  this.map.forEachFeatureAtPixel(evt.pixel, (feature): void => {
    if (feature instanceof Feature) {
      const featureArray = this.selected.getArray();
      const selIndex = featureArray.indexOf(feature);
      if (selIndex === -1) {
        this.selected.push(feature);
        console.log(feature);
        // this.selected.getArray().forEach((feat) => feat.setStyle(editOperations.highlightStyle));
      } else {
        this.selected.remove(feature);
        feature.setStyle(undefined);
      }
    }
  });
}

我想从 onclick 事件中选择地图上的多个要素，但是当我将单击事件传递给另一个函数时， this.map 未定义，并且出现错误无法读取未定义的属性