ERROR TypeError：无法读取属性＆＃39; push＆＃39;在Angular 5中未定义

Question

从html模板调用addAdd（）时出错。

this.personalForm = this.fb.group({
        user: this.fb.group({
            address: this.fb.array([this.addRows()])     
            }),
addRows() {
  return this.fb.group({
    country: ['']});

addAdd() {
  const control:FormArray = this.personalForm.get[`address`] as FormArray;
  control.push(this.addRows());
}

我在哪里做错了

ERROR TypeError: Cannot read property 'push' of undefined

html代码

<button (click)="addAdd()">Add Address</button>
 <div formArrayName="address">
    <div *ngFor="let add of personalForm.controls?.address?.controls; let i=index" [formGroupName]="i">
    <label>Country</label>
  <input type="text" class="form-control"   formControlName="country" 
  placeholder="Country" />
 </div> 
</div>

Answer 1

在这种情况下，控制可能为null，请添加对null和length的检查。

const control:FormArray = this.personalForm.get[`address`] as FormArray;
if(control && control.length >0){
  control.push(this.addRows());
}

Answer 2

get是一个函数，而不是一个对象。此外，您必须指定控件的完整路径。

const control:FormArray = this.personalForm.get(['user', 'address']) as FormArray;

或

const control:FormArray = this.personalForm.get('user.address') as FormArray;

Answer 3

Thanks Marko ! this is working, cool !

addAdd() {
    const control:FormArray = this.personalForm.get('user.address') as FormArray;  
    control.push(this.addRows());  
  }