ng-zorro 级联输入框懒加载时，load方法里this=undefined

Question

如题，代码如下：

<nz-cascader  
  \[nzLoadData\]\="loadCityBuildingData"  
  \[(ngModel)\]\="selectedLocation"  
  (ngModelChange)\="onNewLocationModalChanges($event)"  
\> </nz-cascader>

loadCityBuildingData(node: NzCascaderOption, index: number): PromiseLike<void\> {  
  console.log(this);  
  
 return new Promise(resolve => {  
    if (index < 0) {  
      this.cityService.getCities().subscribe(item => {  
        const cities = \[\];  
  item.forEach(city => {  
          cities.push({value: city.id, label: city.name});  
  });  
  node.children \= cities;  
  resolve();  
  });  
  } else if (index === 0) {  
      this.buildingService.getBuildingsByCityId(node.value).subscribe(item => {  
        const buildings = \[\];  
  item.forEach(building => {  
          buildings.push({value: building.id, label: building.name, isLeaf: true});  
  });  
  node.children \= buildings;  
  resolve();  
  });  
  }  
  });  
}

Answer 1

遇到相同的问题，不知道解决了没 哭o(╥﹏╥)o

Answer 2

用箭头函数，或者绑定this

loadCityBuildingData = (node: NzCascaderOption, index: number): PromiseLike<void> => {  
  console.log(this);  
  
 return new Promise(resolve => {  
    if (index < 0) {  
      this.cityService.getCities().subscribe(item => {  
        const cities = [];  
  item.forEach(city => {  
          cities.push({value: city.id, label: city.name});  
  });  
  node.children = cities;  
  resolve();  
  });  
  } else if (index === 0) {  
      this.buildingService.getBuildingsByCityId(node.value).subscribe(item => {  
        const buildings = [];  
  item.forEach(building => {  
          buildings.push({value: building.id, label: building.name, isLeaf: true});  
  });  
  node.children = buildings;  
  resolve();  
  });  
  }  
  });  
}