title: formArrayName must be used with a parent formGroup directive
body: <p>I'm getting an error: <code>formArrayName must be used with a parent formGroup directive.  You'll want to add a formGroup directive and pass it an existing FormGroup instance</code>. I'm not sure what am I doing wrong.
  I would like the FormGroup to iterate several time(using <code>ngFor</code>), and thought using <code>formArrayName</code> would be the answer.</p>
  
  <blockquote> HTML: </blockquote>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
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  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div formArrayName = "PaymentArray" *ngFor = "let meshalem of paymentForm.get('PaymentArray').controls;let i =index;"&gt;
      &lt;div [formGroup]="i"&gt;
          &lt;div class="row box-border" &gt;
              &lt;div class="form-group col-xs-12 col-sm-12 col-md-5 pull-right required"&gt;
                  &lt;label class="control-label"&gt;מספר ת.ז. משלם&lt;/label&gt;
                  &lt;input #PidField name="id_pay" id="id_pay" formControlName="id_pay" class="form-control input-lg"
                      maxlength="9" (input)="searchChange($event.target.value)" /&gt;
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;</code></pre>
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  <blockquote> .ts File: </blockquote> 
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>  paymentForm = this.fb.group({
      PaymentArray: this.fb.array([])
    })
    
    
    
    getPaymentList()
    {
     
          this._adminService.getPayment(this.id).subscribe(res =&gt; {
              if(res.isSuccess)
              {
                  this.PaymentList = res.data ;
                  this.PaymentList.forEach((pays) =&gt; {
                          this.meshalemArray = this.paymentForm.get('PaymentArray') as FormArray;
                          this.meshalemArray.push(this.fb.group({
                              id_pay:[pays.id_pay,Validators.compose([Validators.pattern("^[0-9]*$"), Validators.required])],
                              numberRooms:[pays.numberRooms],
                              sum: [pays.sum],
                              paymentMethod:[pays.paymentMethod],
                              credit:[pays.credit],
                          }))  
                          
                  })
              }
              else
              {
                //TODO
              }
          })
      
    }</code></pre>
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