如何访问formControlName in ngFor in ngFor (嵌套formArray)？

Question

我是角形2的初学者，我试图创建一个具有动态形式的表，表被创建，值也绑定，但我无法在formControlName中访问值，尝试了下面的代码，但它没有工作。

有谁能帮我看看我在哪里做错了下面的代码？

<tbody formArrayName="timetable">
     <tr *ngFor="let child of timetableForm.controls.timetable.controls; let i = index;" [formGroupName]="i">
        <td *ngFor="let period of child.controls.periods.controls;let j = index;" [formGroupName]="j">
            {{period.controls.day.value}} <!-- bind is working fine -->
            <input type="text" [formControlName]="day">  <!-- error -->                               
        </td>
     </tr>
</tbody>

TS

ngOnInit(){
this.tableForm = this.formBuilder.group({
      timetable: this.formBuilder.array([
             this.formBuilder.group({
                    periods: this.formBuilder.array([
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Monday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Tuesday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Wednesday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Thursday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Friday'
                        })
                    ])
                }),
                this.formBuilder.group({
                    periods: this.formBuilder.array([
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Monday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Tuesday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            day:'Wednesday'
                        }),
                        this.formBuilder.group({
                            subject_id:10,
                            timing_id:11,
                            name:'Thursday'
                        })
                    ])
                })
            ])
         });

提前谢谢。

Answer 1

我发现的第一件事

this.formBuilder.group({
      subject_id:10,
      timing_id:11,
      name:'Thursday'
      ^^^^
 it should be day
})

其次，为什么在模板中使用timetableForm而在组件中创建tableForm？

第三，您应该使用formControlName="day"而不是注释中提到的[formControlName]="day"。

最后，您忘记了在formArrayName="periods"中包装您的子数组。要做到这一点，您可以使用ng-container，如下所示：

<table [formGroup]="tableForm">
    <tbody formArrayName="timetable">
        <tr *ngFor="let child of tableForm.controls.timetable.controls; let i = index;" [formGroupName]="i">
            <ng-container formArrayName="periods">
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                       add this
                <td *ngFor="let period of child.controls.periods.controls;let j = index;" [formGroupName]="j">
                    {{period.controls.day.value}}
                    <input type="text" formControlName="day">
                </td>
            </ng-container>
        </tr>
    </tbody>
</table>

Ng-运行示例