如果在第二个ngFor中，我仅使用subtask.taskID，则一切正常。第二个是我要插入的第二件事，即subtask.taskName，它会中断。
如果我注释掉subtask.taskID并保留subtask.taskName，则一切正常。 为什么会这样呢？为什么我不能在第二个ngFor中显示多个子任务？
编辑：类似的问题。无法显示我的子任务的其他属性。我只能展示一个。我还更新了代码，因为我正在逐步处理此树形网格组件。 stackblitz：https://stackblitz.com/edit/angular-xk9nw6
<H1>Table</H1>
<table class="table">
<thead>
<tr>
<th>expand</th>
<th>task id</th>
<th>task name</th>
<th>button</th>
</tr>
</thead>
<tbody *ngFor="let datum of data">
<tr>
<td class="" (click)="subtask(datum)">> </td>
<td class="">{{datum.taskID}}</td>
<td class="">{{datum.taskName}}</td>
<td class="btn btn.primary" (click)="dropdown(datum)">...</td>
</tr>
<tr [hidden]="!foo" *ngFor="let subtask of datum.subtasks" >
<td class="">> </td>
<td class="">{{subtask?.taskID}}</td>
<td class="">{{substask?.taskName}}</td>
<td class=" btn btn.primary" (click)="dropdown(subtask)">...</td>
</tr>
</tbody>
</table>
样本数据
/**
* Test cases data source
*/
export let sampleData: Object[] = [
{
taskID: 1,
taskName: 'Planning',
startDate: new Date('02/03/2017'),
endDate: new Date('02/07/2017'),
progress: 100,
duration: 5,
priority: 'Normal',
approved: false,
isInExpandState: true,
subtasks: [
{ taskID: 2, taskName: 'Plan timeline', startDate: new Date('02/03/2017'), endDate: new Date('02/07/2017'), duration: 5, progress: 100, priority: 'Normal', approved: false },
{ taskID: 3, taskName: 'Plan budget', startDate: new Date('02/03/2017'), endDate: new Date('02/07/2017'), duration: 5, progress: 100, approved: true },
{ taskID: 4, taskName: 'Allocate resources', startDate: new Date('02/03/2017'), endDate: new Date('02/07/2017'), duration: 5, progress: 100, priority: 'Critical', approved: false },
{ taskID: 5, taskName: 'Planning complete', startDate: new Date('02/07/2017'), endDate: new Date('02/07/2017'), duration: 0, progress: 0, priority: 'Low', approved: true }
]
},
{
taskID: 6,
taskName: 'Design',
startDate: new Date('02/10/2017'),
endDate: new Date('02/14/2017'),
duration: 3,
progress: 86,
priority: 'High',
isInExpandState: false,
approved: false,
subtasks: [
{ taskID: 7, taskName: 'Software Specification', startDate: new Date('02/10/2017'), endDate: new Date('02/12/2017'), duration: 3, progress: 60, priority: 'Normal', approved: false },
{ taskID: 8, taskName: 'Develop prototype', startDate: new Date('02/10/2017'), endDate: new Date('02/12/2017'), duration: 3, progress: 100, priority: 'Critical', approved: false },
{ taskID: 9, taskName: 'Get approval from customer', startDate: new Date('02/13/2017'), endDate: new Date('02/14/2017'), duration: 2, progress: 100, approved: true },
{ taskID: 10, taskName: 'Design Documentation', startDate: new Date('02/13/2017'), endDate: new Date('02/14/2017'), duration: 2, progress: 100, approved: true },
{ taskID: 11, taskName: 'Design complete', startDate: new Date('02/14/2017'), endDate: new Date('02/14/2017'), duration: 0, progress: 0, priority: 'Normal', approved: true }
]
},
{
taskID: 12,
taskName: 'Implementation Phase',
startDate: new Date('02/17/2017'),
endDate: new Date('02/27/2017'),
priority: 'Normal',
approved: false,
duration: 11,
subtasks: [
{
taskID: 13,
taskName: 'Phase 1',
startDate: new Date('02/17/2017'),
endDate: new Date('02/27/2017'),
priority: 'High',
approved: false,
duration: 11,
subtasks: [{
taskID: 14,
taskName: 'Implementation Module 1',
startDate: new Date('02/17/2017'),
endDate: new Date('02/27/2017'),
priority: 'Normal',
duration: 11,
approved: false,
subtasks: [
{ taskID: 15, taskName: 'Development Task 1', startDate: new Date('02/17/2017'), endDate: new Date('02/19/2017'), duration: 3, progress: '50', priority: 'High', approved: false },
{ taskID: 16, taskName: 'Development Task 2', startDate: new Date('02/17/2017'), endDate: new Date('02/19/2017'), duration: 3, progress: '50', priority: 'Low', approved: true },
{ taskID: 17, taskName: 'Testing', startDate: new Date('02/20/2017'), endDate: new Date('02/21/2017'), duration: 2, progress: '0', priority: 'Normal', approved: true },
{ taskID: 18, taskName: 'Bug fix', startDate: new Date('02/24/2017'), endDate: new Date('02/25/2017'), duration: 2, progress: '0', priority: 'Critical', approved: false },
{ taskID: 19, taskName: 'Customer review meeting', startDate: new Date('02/26/2017'), endDate: new Date('02/27/2017'), duration: 2, progress: '0', priority: 'High', approved: false },
{ taskID: 20, taskName: 'Phase 1 complete', startDate: new Date('02/27/2017'), endDate: new Date('02/27/2017'), duration: 0, priority: 'Low', approved: true }
]
}]
},
{
taskID: 21,
taskName: 'Phase 2',
startDate: new Date('02/17/2017'),
endDate: new Date('02/28/2017'),
priority: 'High',
approved: false,
duration: 12,
subtasks: [{
taskID: 22,
taskName: 'Implementation Module 2',
startDate: new Date('02/17/2017'),
endDate: new Date('02/28/2017'),
priority: 'Critical',
approved: false,
duration: 12,
subtasks: [
{ taskID: 23, taskName: 'Development Task 1', startDate: new Date('02/17/2017'), endDate: new Date('02/20/2017'), duration: 4, progress: '50', priority: 'Normal', approved: true },
{ taskID: 24, taskName: 'Development Task 2', startDate: new Date('02/17/2017'), endDate: new Date('02/20/2017'), duration: 4, progress: '50', priority: 'Critical', approved: true },
{ taskID: 25, taskName: 'Testing', startDate: new Date('02/21/2017'), endDate: new Date('02/24/2017'), duration: 2, progress: '0', priority: 'High', approved: false },
{ taskID: 26, taskName: 'Bug fix', startDate: new Date('02/25/2017'), endDate: new Date('02/26/2017'), duration: 2, progress: '0', priority: 'Low', approved: false },
{ taskID: 27, taskName: 'Customer review meeting', startDate: new Date('02/27/2017'), endDate: new Date('02/28/2017'), duration: 2, progress: '0', priority: 'Critical', approved: true },
{ taskID: 28, taskName: 'Phase 2 complete', startDate: new Date('02/28/2017'), endDate: new Date('02/28/2017'), duration: 0, priority: 'Normal', approved: false }
]
}]
},
{
taskID: 29,
taskName: 'Phase 3',
startDate: new Date('02/17/2017'),
endDate: new Date('02/27/2017'),
priority: 'Normal',
approved: false,
duration: 11,
subtasks: [{
taskID: 30,
taskName: 'Implementation Module 3',
startDate: new Date('02/17/2017'),
endDate: new Date('02/27/2017'),
priority: 'High',
approved: false,
duration: 11,
subtasks: [
{ taskID: 31, taskName: 'Development Task 1', startDate: new Date('02/17/2017'), endDate: new Date('02/19/2017'), duration: 3, progress: '50', priority: 'Low', approved: true },
{ taskID: 32, taskName: 'Development Task 2', startDate: new Date('02/17/2017'), endDate: new Date('02/19/2017'), duration: 3, progress: '50', priority: 'Normal', approved: false },
{ taskID: 33, taskName: 'Testing', startDate: new Date('02/20/2017'), endDate: new Date('02/21/2017'), duration: 2, progress: '0', priority: 'Critical', approved: true },
{ taskID: 34, taskName: 'Bug fix', startDate: new Date('02/24/2017'), endDate: new Date('02/25/2017'), duration: 2, progress: '0', priority: 'High', approved: false },
{ taskID: 35, taskName: 'Customer review meeting', startDate: new Date('02/26/2017'), endDate: new Date('02/27/2017'), duration: 2, progress: '0', priority: 'Normal', approved: true },
{ taskID: 36, taskName: 'Phase 3 complete', startDate: new Date('02/27/2017'), endDate: new Date('02/27/2017'), duration: 0, priority: 'Critical', approved: false },
]
}]
}
]
}
];
组件
import { Component, OnInit,ViewChild } from '@angular/core';
import { sampleData } from '../datasource';
@Component({
selector: 'app-table',
templateUrl: './table.component.html',
styleUrls: ['./table.component.css']
})
export class TableComponent implements OnInit {
constructor() { }
@ViewChild('treegrid')
public data: Object[];
public foo: boolean;
dropdown(e){
console.log(e);
}
subtask(e){
console.log(e);
this.foo == false ? this.foo = true : this.foo = false;
}
ngOnInit(): void {
this.data = sampleData;
}
}
答案 0 :(得分：0)
您可以通过使用模板中的安全导航操作符?来解决此问题。这是stackbliz
<H1>Table</H1>
<table *ngFor="let datum of data;" class="table table-bordered table-hover">
<tr>
<td class=""> </td>
<td class="col-sm-2 col-md-2">{{datum?.taskID}}</td>
<td class="col-sm-2 col-md-2">{{datum?.taskName}}</td>
<td class="col-sm-2 col-md-2 btn btn.primary" (click)="dropdown(datum)">...</td>
</tr>
<div *ngIf="datum.subtasks">
<table *ngFor="let subtask of datum.subtasks">
<tr>
<td class="">> </td>
<td class="col-sm-2 col-md-2">{{subtask?.taskID}}</td>
<td class="col-sm-2 col-md-2">{{substask?.taskName}}</td>
<td class="col-sm-2 col-md-2 btn btn.primary" (click)="dropdown(subtask)">...</td>
</tr>
</table>
</div>