angular – PrimeNG TreeTable为空

这是我关注的文档：https://www.primefaces.org/primeng/#/treetable

我正在测试TreeTable功能,但UI中的输出是空的.它显示没有内容的单元格,并且class =“undefined”.

app.component.html：

<p-treeTable *ngIf="treeNode" [value]="treeNode">
  <p-column field="id" header="ID"></p-column>
  <p-column field="label" header="Label"></p-column>
</p-treeTable>

app.module.ts：

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { HttpModule } from '@angular/http';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

import { TreeTableModule,SharedModule } from 'primeng/primeng';

import { AppComponent } from './app.component';
import { CustomerTypeService } from '../app-configure/service/app.customer.type.service';

@NgModule({
  declarations: [
    AppComponent
  ],imports: [
    CommonModule,BrowserModule,HttpModule,BrowserAnimationsModule,TreeTableModule,SharedModule
  ],providers: [CustomerTypeService],bootstrap: [AppComponent]
})
export class AppModule { }

app.component.ts：

import { Component,OnInit } from '@angular/core';
import { TreeNode } from 'primeng/primeng';

import { CustomerTypeService } from '../app-configure/service/app.customer.type.service';

@Component({
  selector: 'app-root',templateUrl: './app.component.html',styleUrls: ['./app.component.css'],providers: []
})
export class AppComponent implements OnInit {
  treeNode: TreeNode[];

  constructor(private customerTypesService: CustomerTypeService) {}

  ngOnInit(): void {
    this.customerTypesService.getCustomerTypes()
        .then(treeNode => {
          this.treeNode = treeNode;
          console.log(this.treeNode);
        });
  }
}

这是我从HTTP请求中获取的JSON字符串：[{“id”：1,“label”：“Account”,“parentId”：null,“parentLabel”：null},{“id”： 2,“label”：“Bank Account”,“parentId”：1,“parentLabel”：“Account”},{“id”：3,“label”：“Test”,“parentLabel” ：空值}]

app.customertype.service.ts：

import { Injectable } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/toPromise';

import {DefaultConfiguration} from '../../app/app.defaults';
import {CustomerType} from '../model/customer.type';
import {TreeNode} from 'primeng/primeng';

@Injectable()
export class CustomerTypeService {
    constructor(private http: Http) {}

    /**
     * Returns an array of all Customer Types.
     * @returns {Promise<CustomerType[]>}
     */
    getCustomerTypes(): Promise<TreeNode[]> {
        return this.http
            .get(`${DefaultConfiguration.BASE_API_URL}/CustomerTypes/`,DefaultConfiguration.getHeaders())
            .toPromise()
            .then(response => <TreeNode[]> response.json())
            .catch(DefaultConfiguration.handleError);
    }
}