NGXS -从子状态访问父状态

import { State, Selector } from '@ngxs/store';

interface ParentStateModel {
  parentProperty: string;
}

interface ChildStateModel {
  childProperty: string;
}

@State<ParentStateModel>({
  name: 'parent',
  defaults: {
    parentProperty: 'Parent Property Value'
  }
})
export class ParentState {}

@State<ChildStateModel>({
  name: 'child',
  defaults: {
    childProperty: 'Child Property Value'
  }
})
export class ChildState {
  @Selector([ParentState])
  static getParentProperty(state: ParentStateModel): string {
    return state.parentProperty;
  }
}

import { Component } from '@angular/core';
import { Select } from '@ngxs/store';
import { ChildState } from './child.state';

@Component({
  selector: 'app-child-component',
  template: `
    <div>{{ parentProperty }}</div>
  `
})
export class ChildComponent {
  @Select(ChildState.getParentProperty) parentProperty: string;
}